diff --git a/.env.example b/.env.example
index 582ab6c4..a32e27f5 100644
--- a/.env.example
+++ b/.env.example
@@ -53,7 +53,8 @@
 
 # ---- 开发用 PostgreSQL（./scripts/dev.sh --postgres）----
 # 这几项只有 dev.sh 读：写成环境变量或写在这个 .env 里都行（环境变量优先）。数据在 docker 数据卷里，
-# 密码第一次自动生成在 data/.postgres-dev/，dev.sh 照它设 AGENTLAB_DATABASE_URL（盖过上面写的）
+# 密码第一次自动生成在数据目录（和后端一样照 AGENTLAB_DATA_DIR，缺省 data/）的 .postgres-dev/ 里，
+# dev.sh 照它设 AGENTLAB_DATABASE_URL（盖过上面写的）
 # AGENTLAB_DEV_PG_CONTAINER=agentlab-dev-postgres
 # AGENTLAB_DEV_PG_PORT=55432
 # AGENTLAB_DEV_PG_VOLUME=agentlab-dev-pgdata
diff --git a/backend/tests/test_deploy_script.py b/backend/tests/test_deploy_script.py
index 77dcc803..022f33a3 100644
--- a/backend/tests/test_deploy_script.py
+++ b/backend/tests/test_deploy_script.py
@@ -813,7 +813,7 @@ def test_env_example_lists_every_database_pool_and_multiprocess_setting():
     names = {f"AGENTLAB_{name.upper()}" for name in Settings.model_fields if name.startswith(prefixes)}
     assert {"AGENTLAB_DATABASE_URL", "AGENTLAB_DATABASE_DIRECT_URL", "AGENTLAB_DB_PGBOUNCER", "AGENTLAB_WORKERS",
             "AGENTLAB_WORKER_LEASE_S", "AGENTLAB_DB_STARTUP_TIMEOUT", "AGENTLAB_SCHEDULER_TICK_S"} <= names
-    dev = set(re.findall(r"dev_pg_setting (AGENTLAB_DEV_PG_[A-Z_]+)", (REPO / "scripts" / "dev.sh").read_text()))
+    dev = set(re.findall(r"dotenv_setting (AGENTLAB_DEV_PG_[A-Z_]+)", (REPO / "scripts" / "dev.sh").read_text()))
     assert len(dev) == 4
     example = (REPO / ".env.example").read_text(encoding="utf-8")
     listed = set(re.findall(r"^# (AGENTLAB_[A-Z_]+)=", example, re.M))
@@ -827,9 +827,12 @@ def test_dev_script_reads_its_postgres_settings_from_dotenv(tmp_path):
     (root / "scripts").mkdir(parents=True)
     (root / "frontend" / "node_modules").mkdir(parents=True)
     shutil.copy(REPO / "scripts" / "dev.sh", root / "scripts" / "dev.sh")
-    (root / "backend").symlink_to(REPO / "backend")
-    (root / ".env").write_text("AGENTLAB_DEV_PG_CONTAINER=from-root-env\nAGENTLAB_DEV_PG_PORT=55491\n"
-                               "AGENTLAB_DEV_PG_VOLUME='quoted-vol'  \n")
+    (root / ".env").write_text("AGENTLAB_DEV_PG_CONTAINER=from-root-env\nAGENTLAB_DEV_PG_PORT = 55491  # 注释\n"
+                               "export AGENTLAB_DEV_PG_VOLUME = 'quoted-vol'  \nAGENTLAB_DATA_DIR=from-root\n")
+    # backend/.env 比 .env 优先（同后端）：数据目录写相对路径，按后端的工作目录 backend/ 算
+    (root / "backend").mkdir()
+    (root / "backend" / ".env").write_text("AGENTLAB_DATA_DIR = ../devdata\n")
+    (root / "backend" / "app").symlink_to(REPO / "backend" / "app")
     bin_dir = tmp_path / "bin"
     bin_dir.mkdir()
     log = tmp_path / "docker.log"
@@ -839,7 +842,7 @@ def test_dev_script_reads_its_postgres_settings_from_dotenv(tmp_path):
                                     'container) exit 1 ;; run) exit 1 ;; esac\nexit 0\n')
     for f in bin_dir.iterdir():
         f.chmod(0o755)
-    env = {"PATH": f"{bin_dir}:/usr/bin:/bin:/usr/sbin:/sbin", "HOME": str(tmp_path), "AGENTLAB_DATA_DIR": str(tmp_path / "data"),
+    env = {"PATH": f"{bin_dir}:/usr/bin:/bin:/usr/sbin:/sbin", "HOME": str(tmp_path),
            "AGENTLAB_DEV_PG_IMAGE": "postgres:from-env", "AGENTLAB_PORT": "18799", "LANG": "C.UTF-8"}
     out = subprocess.run(["bash", str(root / "scripts" / "dev.sh"), "--postgres"], capture_output=True, text=True, env=env,
                          timeout=60)
@@ -848,7 +851,10 @@ def test_dev_script_reads_its_postgres_settings_from_dotenv(tmp_path):
     assert "--name from-root-env" in run and "127.0.0.1:55491:5432" in run, ".env 里的生效"
     assert "quoted-vol:/var/lib/postgresql/data" in run, "引号和行尾空白去掉"
     assert run.endswith("postgres:from-env"), "环境变量优先"
-    (root / "backend").unlink()
+    data = root / "backend" / ".." / "devdata"
+    assert f"{data}/.postgres-dev/password:/run/agentlab/password:ro" in run, "密码放在后端实际用的数据目录里"
+    assert (root / "devdata" / ".postgres-dev" / "pgpass").exists()
+    (root / "backend" / "app").unlink()
 
 
 def test_dev_script_refuses_unknown_arguments_and_documents_postgres():
diff --git a/scripts/dev.sh b/scripts/dev.sh
index 4ed44005..328bafb4 100755
--- a/scripts/dev.sh
+++ b/scripts/dev.sh
@@ -73,19 +73,24 @@ fi
 export AGENTLAB_PORT="$API_PORT"
 
 # ---- --postgres：本地开发用的 PostgreSQL ----
-# 这几项（AGENTLAB_DEV_PG_*）只有这个脚本用。和后端的配置一样认 .env：环境变量 > backend/.env > .env > 缺省（后端的 settings
-# 读这两个文件，后一个优先）。不 source：.env 是给后端按 KEY=VALUE 读的，不是 shell（值里的 $、空格、反引号不该被执行）
+# 这几项（AGENTLAB_DEV_PG_*，还有数据目录 AGENTLAB_DATA_DIR）和后端的配置一样认 .env：环境变量 > backend/.env > .env > 缺省
+# （后端的 settings 读这两个文件，后一个优先）。写法照后端的 dotenv：KEY=value、KEY = value、export KEY=value、引号、行尾 # 注释。
+# 不 source：.env 是给后端按 KEY=VALUE 读的，不是 shell（值里的 $、空格、反引号不该被执行）
 dotenv_value() {
-  local key="$1" file line val="" found=""
+  local key="$1" file line name val="" found=""
   for file in "$ROOT/.env" "$ROOT/backend/.env"; do
     [ -f "$file" ] || continue
     while IFS= read -r line || [ -n "$line" ]; do
       line="${line%$'\r'}"
       line="${line#"${line%%[![:space:]]*}"}"
       line="${line#export }"
-      case "$line" in
-        "$key="*) val="${line#*=}"; found=1 ;;
-      esac
+      case "$line" in *=*) ;; *) continue ;; esac
+      name="${line%%=*}"
+      name="${name%"${name##*[![:space:]]}"}"
+      [ "$name" = "$key" ] || continue
+      val="${line#*=}"
+      val="${val#"${val%%[![:space:]]*}"}"
+      found=1
     done < "$file"
   done
   [ -n "$found" ] || return 1
@@ -96,18 +101,20 @@ dotenv_value() {
   esac
   printf '%s' "$val"
 }
-dev_pg_setting() {
+dotenv_setting() {
   local value
   value="$(printenv "$1" 2>/dev/null || true)"
   [ -n "$value" ] || value="$(dotenv_value "$1" || true)"
   printf '%s' "${value:-$2}"
 }
 if [ -n "$WITH_PG" ]; then
-  PG_CONTAINER="$(dev_pg_setting AGENTLAB_DEV_PG_CONTAINER agentlab-dev-postgres)"
-  PG_PORT="$(dev_pg_setting AGENTLAB_DEV_PG_PORT 55432)"
-  PG_VOLUME="$(dev_pg_setting AGENTLAB_DEV_PG_VOLUME agentlab-dev-pgdata)"
-  PG_IMAGE="$(dev_pg_setting AGENTLAB_DEV_PG_IMAGE postgres:16)"
-  DEV_DATA="${AGENTLAB_DATA_DIR:-$ROOT/data}"
+  PG_CONTAINER="$(dotenv_setting AGENTLAB_DEV_PG_CONTAINER agentlab-dev-postgres)"
+  PG_PORT="$(dotenv_setting AGENTLAB_DEV_PG_PORT 55432)"
+  PG_VOLUME="$(dotenv_setting AGENTLAB_DEV_PG_VOLUME agentlab-dev-pgdata)"
+  PG_IMAGE="$(dotenv_setting AGENTLAB_DEV_PG_IMAGE postgres:16)"
+  # 密码文件放在后端实际用的数据目录里：和后端一样读 AGENTLAB_DATA_DIR，相对路径按后端的工作目录（backend/）算
+  DEV_DATA="$(dotenv_setting AGENTLAB_DATA_DIR "$ROOT/data")"
+  case "$DEV_DATA" in /*) ;; *) DEV_DATA="$ROOT/backend/$DEV_DATA" ;; esac
   case "$PG_PORT" in ''|*[!0-9]*) echo "AGENTLAB_DEV_PG_PORT 要是端口号：$PG_PORT"; exit 2 ;; esac
   command -v docker >/dev/null || { echo "--postgres 要用 docker，没找到它"; exit 1; }
   docker version --format '{{.Server.Version}}' >/dev/null 2>&1 || { echo "连不上 docker 服务，先把 Docker 启动起来"; exit 1; }