diff --git a/mmeval/metrics/word_accuracy.py b/mmeval/metrics/word_accuracy.py
index a446fe8c..a51f00aa 100644
--- a/mmeval/metrics/word_accuracy.py
+++ b/mmeval/metrics/word_accuracy.py
@@ -19,8 +19,8 @@ class WordAccuracy(BaseMetric):
 
             If mode is a list, then metrics in mode will be calculated
             separately. Defaults to 'ignore_case_symbol'.
-        valid_symbol (str): Valid characters. Defaults to
-            '[^A-Z^a-z^0-9^\u4e00-\u9fa5]'.
+        invalid_symbol (str): A regular expression to filter out invalid or
+            not cared characters. Defaults to '[^A-Za-z0-9\u4e00-\u9fa5]'
 
     Example:
         >>> from mmeval import WordAccuracy
@@ -37,11 +37,11 @@ class WordAccuracy(BaseMetric):
 
     def __init__(self,
                  mode: Union[str, Sequence[str]] = 'ignore_case_symbol',
-                 valid_symbol: str = '[^A-Z^a-z^0-9^\u4e00-\u9fa5]',
+                 invalid_symbol: str = '[^A-Za-z0-9\u4e00-\u9fa5]',
                  **kwargs):
         super().__init__(**kwargs)
         self.mode = mode
-        self.valid_symbol = re.compile(valid_symbol)
+        self.invalid_symbol = re.compile(invalid_symbol)
         assert isinstance(mode, (str, list))
         if isinstance(mode, str):
             mode = [mode]
@@ -66,8 +66,8 @@ def add(self, predictions: Sequence[str], labels: Sequence[str]) -> None:  # typ
                 label_lower = label.lower()
                 ignore_case_num = pred_lower == label_lower
             if 'ignore_case_symbol' in self.mode:
-                label_lower_ignore = self.valid_symbol.sub('', label_lower)
-                pred_lower_ignore = self.valid_symbol.sub('', pred_lower)
+                label_lower_ignore = self.invalid_symbol.sub('', label_lower)
+                pred_lower_ignore = self.invalid_symbol.sub('', pred_lower)
                 ignore_case_symbol_num =\
                     label_lower_ignore == pred_lower_ignore
             self._results.append(
diff --git a/tests/test_metrics/test_word_accuracy.py b/tests/test_metrics/test_word_accuracy.py
index 4898d96a..db9ee883 100644
--- a/tests/test_metrics/test_word_accuracy.py
+++ b/tests/test_metrics/test_word_accuracy.py
@@ -20,3 +20,11 @@ def test_word_accuracy():
     assert abs(res['accuracy'] - 1. / 3) < 1e-7
     assert abs(res['ignore_case_accuracy'] - 2. / 3) < 1e-7
     assert abs(res['ignore_case_symbol_accuracy'] - 1.0) < 1e-7
+    metric.reset()
+    for pred, label in zip(['hello', 'hello', 'hello'],
+                           ['hello', 'HELLO', '$HELLO$']):
+        metric.add([pred], [label])
+    res = metric.compute()
+    assert abs(res['accuracy'] - 1. / 3) < 1e-7
+    assert abs(res['ignore_case_accuracy'] - 2. / 3) < 1e-7
+    assert abs(res['ignore_case_symbol_accuracy'] - 1.0) < 1e-7