diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/scalar/Coalesce.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/scalar/Coalesce.java
index 2ed864ba9a0c30..df211926c02a3b 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/scalar/Coalesce.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/scalar/Coalesce.java
@@ -19,61 +19,27 @@
 
 import org.apache.doris.catalog.FunctionSignature;
 import org.apache.doris.nereids.trees.expressions.Expression;
-import org.apache.doris.nereids.trees.expressions.functions.ExplicitlyCastableSignature;
+import org.apache.doris.nereids.trees.expressions.functions.CustomSignature;
+import org.apache.doris.nereids.trees.expressions.functions.ExpressionTrait;
+import org.apache.doris.nereids.trees.expressions.functions.SearchSignature;
+import org.apache.doris.nereids.trees.expressions.literal.Literal;
 import org.apache.doris.nereids.trees.expressions.visitor.ExpressionVisitor;
-import org.apache.doris.nereids.types.BigIntType;
-import org.apache.doris.nereids.types.BitmapType;
-import org.apache.doris.nereids.types.BooleanType;
-import org.apache.doris.nereids.types.DateTimeType;
-import org.apache.doris.nereids.types.DateTimeV2Type;
-import org.apache.doris.nereids.types.DateType;
-import org.apache.doris.nereids.types.DateV2Type;
-import org.apache.doris.nereids.types.DecimalV2Type;
-import org.apache.doris.nereids.types.DecimalV3Type;
-import org.apache.doris.nereids.types.DoubleType;
-import org.apache.doris.nereids.types.FloatType;
-import org.apache.doris.nereids.types.IntegerType;
-import org.apache.doris.nereids.types.LargeIntType;
-import org.apache.doris.nereids.types.SmallIntType;
-import org.apache.doris.nereids.types.StringType;
-import org.apache.doris.nereids.types.TimeType;
-import org.apache.doris.nereids.types.TimeV2Type;
-import org.apache.doris.nereids.types.TinyIntType;
-import org.apache.doris.nereids.types.VarcharType;
+import org.apache.doris.nereids.types.DataType;
 import org.apache.doris.nereids.util.ExpressionUtils;
+import org.apache.doris.nereids.util.TypeCoercionUtils;
 
 import com.google.common.base.Preconditions;
-import com.google.common.collect.ImmutableList;
+import com.google.common.collect.Lists;
 
 import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.stream.Collectors;
 
 /**
  * ScalarFunction 'coalesce'. This class is generated by GenerateFunction.
  */
-public class Coalesce extends ScalarFunction
-        implements ExplicitlyCastableSignature {
-
-    public static final List<FunctionSignature> SIGNATURES = ImmutableList.of(
-            FunctionSignature.ret(BooleanType.INSTANCE).varArgs(BooleanType.INSTANCE),
-            FunctionSignature.ret(TinyIntType.INSTANCE).varArgs(TinyIntType.INSTANCE),
-            FunctionSignature.ret(SmallIntType.INSTANCE).varArgs(SmallIntType.INSTANCE),
-            FunctionSignature.ret(IntegerType.INSTANCE).varArgs(IntegerType.INSTANCE),
-            FunctionSignature.ret(BigIntType.INSTANCE).varArgs(BigIntType.INSTANCE),
-            FunctionSignature.ret(LargeIntType.INSTANCE).varArgs(LargeIntType.INSTANCE),
-            FunctionSignature.ret(DoubleType.INSTANCE).varArgs(DoubleType.INSTANCE),
-            FunctionSignature.ret(FloatType.INSTANCE).varArgs(FloatType.INSTANCE),
-            FunctionSignature.ret(DateTimeV2Type.SYSTEM_DEFAULT).varArgs(DateTimeV2Type.SYSTEM_DEFAULT),
-            FunctionSignature.ret(DateTimeType.INSTANCE).varArgs(DateTimeType.INSTANCE),
-            FunctionSignature.ret(DateV2Type.INSTANCE).varArgs(DateV2Type.INSTANCE),
-            FunctionSignature.ret(DateType.INSTANCE).varArgs(DateType.INSTANCE),
-            FunctionSignature.ret(TimeType.INSTANCE).varArgs(TimeType.INSTANCE),
-            FunctionSignature.ret(TimeV2Type.INSTANCE).varArgs(TimeV2Type.INSTANCE),
-            FunctionSignature.ret(DecimalV3Type.WILDCARD).varArgs(DecimalV3Type.WILDCARD),
-            FunctionSignature.ret(DecimalV2Type.SYSTEM_DEFAULT).varArgs(DecimalV2Type.SYSTEM_DEFAULT),
-            FunctionSignature.ret(BitmapType.INSTANCE).varArgs(BitmapType.INSTANCE),
-            FunctionSignature.ret(VarcharType.SYSTEM_DEFAULT).varArgs(VarcharType.SYSTEM_DEFAULT),
-            FunctionSignature.ret(StringType.INSTANCE).varArgs(StringType.INSTANCE)
-    );
+public class Coalesce extends ScalarFunction implements CustomSignature {
 
     /**
      * constructor with 1 or more arguments.
@@ -106,8 +72,33 @@ public Coalesce withChildren(List<Expression> children) {
     }
 
     @Override
-    public List<FunctionSignature> getSignatures() {
-        return SIGNATURES;
+    public FunctionSignature customSignature() {
+        Map<Boolean, List<Expression>> partitioned = getArguments().stream()
+                .collect(Collectors.partitioningBy(
+                    e -> (e instanceof Literal && ((Literal) e).isStringLikeLiteral())));
+        List<DataType> forFindCommon = partitioned.get(false).stream()
+                .map(ExpressionTrait::getDataType)
+                .collect(Collectors.toList());
+        Optional<DataType> commonType = TypeCoercionUtils.findWiderCommonTypeForCaseWhen(forFindCommon);
+        if (!commonType.isPresent()) {
+            SearchSignature.throwCanNotFoundFunctionException(this.getName(), getArguments());
+            return null;
+        } else {
+            for (Expression stringLiteral : partitioned.get(true)) {
+                Optional<Expression> option = TypeCoercionUtils.characterLiteralTypeCoercion(
+                        ((Literal) stringLiteral).getStringValue(), commonType.get());
+                if (!option.isPresent()) {
+                    List<DataType> commonTypes = Lists.newArrayList(commonType.get(), stringLiteral.getDataType());
+                    commonType = TypeCoercionUtils.findWiderCommonTypeForCaseWhen(commonTypes);
+                    if (!commonType.isPresent()) {
+                        SearchSignature.throwCanNotFoundFunctionException(this.getName(), getArguments());
+                    } else {
+                        break;
+                    }
+                }
+            }
+            return FunctionSignature.ret(commonType.get()).varArgs(commonType.get());
+        }
     }
 
     @Override
diff --git a/fe/fe-core/src/test/java/org/apache/doris/nereids/rules/expression/rules/SimplifyConditionalFunctionTest.java b/fe/fe-core/src/test/java/org/apache/doris/nereids/rules/expression/rules/SimplifyConditionalFunctionTest.java
index 152c0f542e3140..a2831e8cd2c13d 100644
--- a/fe/fe-core/src/test/java/org/apache/doris/nereids/rules/expression/rules/SimplifyConditionalFunctionTest.java
+++ b/fe/fe-core/src/test/java/org/apache/doris/nereids/rules/expression/rules/SimplifyConditionalFunctionTest.java
@@ -60,10 +60,10 @@ public void testCoalesce() {
         assertRewrite(new Coalesce(slot, nonNullableSlot), new Coalesce(slot, nonNullableSlot));
 
         // coalesce(null, null) -> null
-        assertRewrite(new Coalesce(NullLiteral.INSTANCE, NullLiteral.INSTANCE), new NullLiteral(BooleanType.INSTANCE));
+        assertRewrite(new Coalesce(NullLiteral.INSTANCE, NullLiteral.INSTANCE), NullLiteral.INSTANCE);
 
         // coalesce(null) -> null
-        assertRewrite(new Coalesce(NullLiteral.INSTANCE), new NullLiteral(BooleanType.INSTANCE));
+        assertRewrite(new Coalesce(NullLiteral.INSTANCE), NullLiteral.INSTANCE);
 
         // coalesce(non-nullable_slot) -> non-nullable_slot
         assertRewrite(new Coalesce(nonNullableSlot), nonNullableSlot);