diff --git a/src/main/java/org/redkale/convert/EnMember.java b/src/main/java/org/redkale/convert/EnMember.java
index 462f55bea..39edfc8f1 100644
--- a/src/main/java/org/redkale/convert/EnMember.java
+++ b/src/main/java/org/redkale/convert/EnMember.java
@@ -219,7 +219,7 @@ public final class EnMember<W extends Writer, T, F> {
 
     @Override
     public String toString() {
-        return "EnMember{" + "attribute=" + attribute.field() + ", position=" + position + ", encoder="
+        return "EnMember{" + "attribute=" + attribute.field() + ", position=" + position + ", tag=" + tag + ", encoder="
                 + (encoder == null ? null : encoder.getClass().getName()) + '}';
     }
 }
diff --git a/src/main/java/org/redkale/convert/pb/ProtobufFactory.java b/src/main/java/org/redkale/convert/pb/ProtobufFactory.java
index 32c7b17c5..d6e1d3464 100644
--- a/src/main/java/org/redkale/convert/pb/ProtobufFactory.java
+++ b/src/main/java/org/redkale/convert/pb/ProtobufFactory.java
@@ -25,7 +25,7 @@ public class ProtobufFactory extends ConvertFactory<ProtobufReader, ProtobufWrit
                             "redkale.convert.nullable",
                             false,
                             Convert.FEATURE_NULLABLE),
-            Boolean.parseBoolean(System.getProperty("redkale.convert.protobuf.enumtostring", "true")));
+            Boolean.parseBoolean(System.getProperty("redkale.convert.protobuf.enumtostring", "false")));
 
     static final Decodeable objectDecoder = instance.loadDecoder(Object.class);
 
diff --git a/src/main/java/org/redkale/convert/pb/ProtobufWriter.java b/src/main/java/org/redkale/convert/pb/ProtobufWriter.java
index 5469cdf44..865de8e15 100644
--- a/src/main/java/org/redkale/convert/pb/ProtobufWriter.java
+++ b/src/main/java/org/redkale/convert/pb/ProtobufWriter.java
@@ -410,8 +410,10 @@ public class ProtobufWriter extends Writer implements ByteTuple {
             value = objFieldFunc.apply(member.getAttribute(), obj);
         }
         if (value == null) {
-            this.writeFieldName(member);
-            writeNull();
+            if (nullable()) {
+                this.writeFieldName(member);
+                writeNull();
+            }
             return;
         }
         if (tiny()) {