diff --git a/qlib/backtest/__init__.py b/qlib/backtest/__init__.py
index 9daba911533..e6bde47c745 100644
--- a/qlib/backtest/__init__.py
+++ b/qlib/backtest/__init__.py
@@ -116,6 +116,7 @@ def create_account_instance(
     benchmark: Optional[str],
     account: Union[float, int, dict],
     pos_type: str = "Position",
+    freq: str = "day",
 ) -> Account:
     """
     # TODO: is very strange pass benchmark_config in the account (maybe for report)
@@ -161,6 +162,7 @@ def create_account_instance(
     return Account(
         init_cash=init_cash,
         position_dict=position_dict,
+        freq=freq,
         pos_type=pos_type,
         benchmark_config=(
             {}
@@ -183,6 +185,7 @@ def get_strategy_executor(
     account: Union[float, int, dict] = 1e9,
     exchange_kwargs: dict = {},
     pos_type: str = "Position",
+    freq: str = "day",
 ) -> Tuple[BaseStrategy, BaseExecutor]:
     # NOTE:
     # - for avoiding recursive import
@@ -196,6 +199,7 @@ def get_strategy_executor(
         benchmark=benchmark,
         account=account,
         pos_type=pos_type,
+        freq=freq,
     )
 
     exchange_kwargs = copy.copy(exchange_kwargs)
@@ -223,6 +227,7 @@ def backtest(
     account: Union[float, int, dict] = 1e9,
     exchange_kwargs: dict = {},
     pos_type: str = "Position",
+    freq: str = "day",
 ) -> Tuple[PORT_METRIC, INDICATOR_METRIC]:
     """initialize the strategy and executor, then backtest function for the interaction of the outermost strategy and
     executor in the nested decision execution
@@ -272,6 +277,7 @@ def backtest(
         account,
         exchange_kwargs,
         pos_type=pos_type,
+        freq=freq,
     )
     return backtest_loop(start_time, end_time, trade_strategy, trade_executor)
 
@@ -286,6 +292,7 @@ def collect_data(
     exchange_kwargs: dict = {},
     pos_type: str = "Position",
     return_value: dict | None = None,
+    freq: str = "day",
 ) -> Generator[object, None, None]:
     """initialize the strategy and executor, then collect the trade decision data for rl training
 
@@ -305,6 +312,7 @@ def collect_data(
         account,
         exchange_kwargs,
         pos_type=pos_type,
+        freq=freq,
     )
     yield from collect_data_loop(start_time, end_time, trade_strategy, trade_executor, return_value=return_value)
 
diff --git a/tests/test_backtest_account_freq.py b/tests/test_backtest_account_freq.py
new file mode 100644
index 00000000000..1075fbfa090
--- /dev/null
+++ b/tests/test_backtest_account_freq.py
@@ -0,0 +1,72 @@
+"""Test for Issue #1846: Backtest should thread freq to Account, not hardcode 'day'."""
+import pytest
+from unittest.mock import patch
+from qlib.backtest import create_account_instance
+from qlib.backtest.account import Account
+
+
+class TestBacktestAccountFreq:
+    """Verify that freq parameter flows from backtest config to Account."""
+
+    def test_account_direct_freq_day(self):
+        """Account class should default to freq='day'."""
+        account = Account(init_cash=1e6, freq="day", port_metr_enabled=False)
+        assert account.freq == "day"
+
+    def test_account_direct_freq_custom(self):
+        """Account class should store custom freq."""
+        account = Account(init_cash=1e6, freq="30min", port_metr_enabled=False)
+        assert account.freq == "30min"
+
+    def test_account_direct_freq_60min(self):
+        """Verify 60min freq is threaded correctly to Account."""
+        account = Account(init_cash=1e6, freq="60min", port_metr_enabled=False)
+        assert account.freq == "60min"
+
+    @patch("qlib.backtest.Account")
+    def test_create_account_instance_passes_freq(self, mock_account_cls):
+        """create_account_instance should forward freq to Account constructor."""
+        mock_account_cls.return_value = mock_account_cls
+        create_account_instance(
+            start_time="2020-01-01",
+            end_time="2020-12-31",
+            benchmark=None,
+            account=1e6,
+            freq="60min",
+        )
+        # Verify Account was called with freq="60min"
+        mock_account_cls.assert_called_once()
+        call_kwargs = mock_account_cls.call_args
+        assert call_kwargs.kwargs.get("freq") == "60min" or \
+               (len(call_kwargs.args) > 2 and call_kwargs.args[2] == "60min")
+
+    @patch("qlib.backtest.Account")
+    def test_create_account_instance_default_freq_is_day(self, mock_account_cls):
+        """create_account_instance without freq should default to 'day'."""
+        mock_account_cls.return_value = mock_account_cls
+        create_account_instance(
+            start_time="2020-01-01",
+            end_time="2020-12-31",
+            benchmark=None,
+            account=1e6,
+        )
+        call_kwargs = mock_account_cls.call_args
+        assert call_kwargs.kwargs.get("freq") == "day"
+
+    @patch("qlib.backtest.Account")
+    def test_create_account_freq_not_hardcoded(self, mock_account_cls):
+        """Ensure freq='1min' doesn't silently become 'day'."""
+        mock_account_cls.return_value = mock_account_cls
+        create_account_instance(
+            start_time="2020-01-01",
+            end_time="2020-12-31",
+            benchmark=None,
+            account=1e6,
+            freq="1min",
+        )
+        call_kwargs = mock_account_cls.call_args
+        assert call_kwargs.kwargs.get("freq") == "1min"
+
+
+if __name__ == "__main__":
+    pytest.main([__file__, "-v"])