diff --git a/Source/Modules/ControllerModules/KeyHandler.mm b/Source/Modules/ControllerModules/KeyHandler.mm
index 82770558..78e760e8 100644
--- a/Source/Modules/ControllerModules/KeyHandler.mm
+++ b/Source/Modules/ControllerModules/KeyHandler.mm
@@ -208,7 +208,17 @@ static NSString *const kGraphVizOutputfile = @"/tmp/vChewing-visualization.dot";
         // If the length of the readings and the characters do not match,
         // it often means it is a special symbol and it should not be stored
         // in the user override model.
-        if (selectedNode.spanningLength == [value count]) {
+        BOOL addToOverrideModel = YES;
+        if (selectedNode.spanningLength != [value count]) {
+            addToOverrideModel = NO;
+        }
+        if (addToOverrideModel) {
+            double score = selectedNode.node->scoreForCandidate(stringValue);
+            if (score <= -12) { // 威注音的 SymbolLM 的 Score 是 -12。
+                addToOverrideModel = NO;
+            }
+        }
+        if (addToOverrideModel) {
             _userOverrideModel->observe(_walkedNodes, cursorIndex, stringValue, [[NSDate date] timeIntervalSince1970]);
         }
     }
diff --git a/Source/Modules/LanguageParsers/Gramambular/Node.h b/Source/Modules/LanguageParsers/Gramambular/Node.h
index ff1d3fd2..dfc961c5 100644
--- a/Source/Modules/LanguageParsers/Gramambular/Node.h
+++ b/Source/Modules/LanguageParsers/Gramambular/Node.h
@@ -184,15 +184,15 @@ inline const std::string& Node::key() const { return m_key; }
 
 inline double Node::score() const { return m_score; }
 
-// Prevents the override model to remember symbols with scode -X or lower.
-//inline double Node::scoreForCandidate(const std::string& candidate) const {
-//    for (auto unigram : m_unigrams) {
-//        if (unigram.keyValue.value == candidate) {
-//            return unigram.score;
-//        }
-//    }
-//    return 0.0;
-//}
+
+inline double Node::scoreForCandidate(const std::string& candidate) const {
+    for (auto unigram : m_unigrams) {
+        if (unigram.keyValue.value == candidate) {
+            return unigram.score;
+        }
+    }
+    return 0.0;
+}
 
 inline double Node::highestUnigramScore() const {
     if (m_unigrams.empty()) {