diff --git a/sanguo_trader/persistence.py b/sanguo_trader/persistence.py
new file mode 100644
index 0000000..73ca300
--- /dev/null
+++ b/sanguo_trader/persistence.py
@@ -0,0 +1,173 @@
+"""模拟盘 SQLite 持久化（4 表 + checkpoint + WAL，spec §8 / §9.1）。
+
+表：paper_accounts / paper_trades / paper_positions / paper_daily_balance
+WAL 模式支持 worker 进程写 + 主进程读（spec §9.1 共享 DB 进度）。
+"""
+import json
+import sqlite3
+from datetime import datetime, timezone
+from pathlib import Path
+from typing import Any
+
+SCHEMA = """
+CREATE TABLE IF NOT EXISTS paper_accounts (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    task_id TEXT, owner_id TEXT DEFAULT 'admin', name TEXT,
+    mode TEXT, interval TEXT,
+    symbols TEXT, strategies TEXT,
+    initial_capital REAL, rate REAL, slippage REAL, size REAL, pricetick REAL,
+    stamp_duty_rate REAL, transfer_fee_rate REAL, min_commission REAL,
+    status TEXT, start_date TEXT, end_date TEXT,
+    last_run_date TEXT, next_run_at TEXT, scheduler_job_id TEXT,
+    checkpoint_date TEXT, error_msg TEXT,
+    created_at TEXT, updated_at TEXT
+);
+CREATE TABLE IF NOT EXISTS paper_trades (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    account_id INTEGER, strategy_id TEXT, datetime TEXT, symbol TEXT,
+    direction TEXT, offset TEXT, match_session TEXT,
+    price REAL, volume INTEGER,
+    commission REAL, stamp_duty REAL, transfer_fee REAL,
+    rejected INTEGER, reject_reason TEXT, bar_date TEXT,
+    blocked_by_strategy_id TEXT
+);
+CREATE TABLE IF NOT EXISTS paper_positions (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    account_id INTEGER, scope TEXT, symbol TEXT, date TEXT,
+    volume INTEGER, frozen INTEGER, avg_price REAL, market_value REAL,
+    updated_at TEXT
+);
+CREATE TABLE IF NOT EXISTS paper_daily_balance (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    account_id INTEGER, date TEXT,
+    cash REAL, market_value REAL, total_equity REAL,
+    per_strategy_pnl TEXT, is_checkpoint INTEGER
+);
+"""
+
+
+def _now() -> str:
+    return datetime.now(timezone.utc).isoformat()
+
+
+def init_db(db_path: str) -> None:
+    Path(db_path).parent.mkdir(parents=True, exist_ok=True)
+    with sqlite3.connect(db_path) as conn:
+        conn.executescript(SCHEMA)
+        conn.execute("PRAGMA journal_mode=WAL")
+        conn.commit()
+
+
+def save_account(db_path: str, account: dict[str, Any]) -> int:
+    with sqlite3.connect(db_path) as conn:
+        cur = conn.execute(
+            """INSERT INTO paper_accounts
+               (task_id, owner_id, name, mode, interval, symbols, strategies,
+                initial_capital, rate, slippage, size, pricetick,
+                stamp_duty_rate, transfer_fee_rate, min_commission,
+                status, start_date, end_date, created_at, updated_at)
+               VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)""",
+            (
+                account.get("task_id"), account.get("owner_id", "admin"),
+                account.get("name"), account.get("mode"), account.get("interval"),
+                json.dumps(account.get("symbols", [])),
+                json.dumps(account.get("strategies", [])),
+                account.get("initial_capital", 0), account.get("rate", 0.0003),
+                account.get("slippage", 0), account.get("size", 1),
+                account.get("pricetick", 0.01),
+                account.get("stamp_duty_rate", 0.0005),
+                account.get("transfer_fee_rate", 0.00001),
+                account.get("min_commission", 5.0),
+                account.get("status", "pending"), account.get("start_date"),
+                account.get("end_date"), _now(), _now(),
+            ),
+        )
+        conn.commit()
+        return cur.lastrowid
+
+
+def update_account_status(db_path: str, account_id: int, status: str,
+                          error_msg: str = "") -> None:
+    with sqlite3.connect(db_path) as conn:
+        conn.execute(
+            "UPDATE paper_accounts SET status=?, error_msg=?, updated_at=? WHERE id=?",
+            (status, error_msg, _now(), account_id),
+        )
+        conn.commit()
+
+
+def save_trade(db_path: str, account_id: int, trade: dict[str, Any],
+               rejected: bool = False, reject_reason: str = "") -> int:
+    with sqlite3.connect(db_path) as conn:
+        cur = conn.execute(
+            """INSERT INTO paper_trades
+               (account_id, strategy_id, datetime, symbol, direction, offset,
+                match_session, price, volume, commission, stamp_duty, transfer_fee,
+                rejected, reject_reason, bar_date, blocked_by_strategy_id)
+               VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)""",
+            (
+                account_id, trade.get("strategy_id", ""), trade.get("datetime", ""),
+                trade.get("symbol", ""), trade.get("direction", ""),
+                trade.get("offset", ""), trade.get("match_session", ""),
+                trade.get("price", 0), trade.get("volume", 0),
+                trade.get("commission", 0), trade.get("stamp_duty", 0),
+                trade.get("transfer_fee", 0),
+                1 if rejected else 0, reject_reason, trade.get("bar_date", ""),
+                trade.get("blocked_by_strategy_id"),
+            ),
+        )
+        conn.commit()
+        return cur.lastrowid
+
+
+def save_daily_balance(db_path: str, account_id: int, date: str, cash: float,
+                       market_value: float, total_equity: float,
+                       per_strategy_pnl: dict | None = None,
+                       is_checkpoint: bool = False) -> None:
+    with sqlite3.connect(db_path) as conn:
+        conn.execute(
+            """INSERT INTO paper_daily_balance
+               (account_id, date, cash, market_value, total_equity,
+                per_strategy_pnl, is_checkpoint)
+               VALUES (?,?,?,?,?,?,?)""",
+            (account_id, date, cash, market_value, total_equity,
+             json.dumps(per_strategy_pnl or {}), 1 if is_checkpoint else 0),
+        )
+        conn.commit()
+
+
+def update_checkpoint(db_path: str, account_id: int, date: str) -> None:
+    with sqlite3.connect(db_path) as conn:
+        conn.execute(
+            "UPDATE paper_accounts SET checkpoint_date=?, updated_at=? WHERE id=?",
+            (date, _now(), account_id),
+        )
+        conn.commit()
+
+
+def load_checkpoint(db_path: str, account_id: int) -> str | None:
+    with sqlite3.connect(db_path) as conn:
+        cur = conn.execute(
+            "SELECT checkpoint_date FROM paper_accounts WHERE id=?", (account_id,)
+        )
+        row = cur.fetchone()
+        return row[0] if row else None
+
+
+def list_trades(db_path: str, account_id: int) -> list[dict]:
+    with sqlite3.connect(db_path) as conn:
+        conn.row_factory = sqlite3.Row
+        cur = conn.execute(
+            "SELECT * FROM paper_trades WHERE account_id=? ORDER BY id", (account_id,)
+        )
+        return [dict(r) for r in cur.fetchall()]
+
+
+def list_daily_balance(db_path: str, account_id: int) -> list[dict]:
+    with sqlite3.connect(db_path) as conn:
+        conn.row_factory = sqlite3.Row
+        cur = conn.execute(
+            "SELECT * FROM paper_daily_balance WHERE account_id=? ORDER BY date",
+            (account_id,),
+        )
+        return [dict(r) for r in cur.fetchall()]
diff --git a/tests/trader/test_persistence.py b/tests/trader/test_persistence.py
new file mode 100644
index 0000000..22b8888
--- /dev/null
+++ b/tests/trader/test_persistence.py
@@ -0,0 +1,61 @@
+"""persistence 4 表 round-trip 测试（spec §8）。"""
+from sanguo_trader.persistence import (
+    init_db, save_account, save_trade, save_daily_balance,
+    update_account_status, update_checkpoint, load_checkpoint,
+    list_trades, list_daily_balance,
+)
+
+
+def test_init_and_save_account(tmp_path):
+    db = str(tmp_path / "p.db")
+    init_db(db)
+    aid = save_account(db, {"name": "test", "mode": "replay", "initial_capital": 1_000_000})
+    assert aid > 0
+
+
+def test_save_trade_and_list(tmp_path):
+    db = str(tmp_path / "p.db")
+    init_db(db)
+    aid = save_account(db, {"name": "t"})
+    save_trade(db, aid, {"strategy_id": "s1", "symbol": "600000",
+                         "price": 10.0, "volume": 100, "commission": 5.0})
+    trades = list_trades(db, aid)
+    assert len(trades) == 1
+    assert trades[0]["price"] == 10.0
+    assert trades[0]["rejected"] == 0
+
+
+def test_save_reject_trade(tmp_path):
+    db = str(tmp_path / "p.db")
+    init_db(db)
+    aid = save_account(db, {"name": "t"})
+    save_trade(db, aid, {"symbol": "300750"}, rejected=True,
+               reject_reason="limit_up_locked")
+    trades = list_trades(db, aid)
+    assert trades[0]["rejected"] == 1
+    assert trades[0]["reject_reason"] == "limit_up_locked"
+
+
+def test_daily_balance_and_checkpoint(tmp_path):
+    db = str(tmp_path / "p.db")
+    init_db(db)
+    aid = save_account(db, {"name": "t"})
+    save_daily_balance(db, aid, "2024-01-01", 999_000, 1000, 1_000_000,
+                      per_strategy_pnl={"s1": 100}, is_checkpoint=True)
+    save_daily_balance(db, aid, "2024-01-02", 998_000, 1100, 999_000,
+                      is_checkpoint=False)
+    update_checkpoint(db, aid, "2024-01-01")
+    assert load_checkpoint(db, aid) == "2024-01-01"
+    balances = list_daily_balance(db, aid)
+    assert len(balances) == 2
+    assert balances[0]["is_checkpoint"] == 1
+
+
+def test_update_account_status(tmp_path):
+    db = str(tmp_path / "p.db")
+    init_db(db)
+    aid = save_account(db, {"name": "t", "status": "pending"})
+    update_account_status(db, aid, "done")
+    with __import__("sqlite3").connect(db) as conn:
+        row = conn.execute("SELECT status FROM paper_accounts WHERE id=?", (aid,)).fetchone()
+        assert row[0] == "done"