diff --git a/src/main/java/com/kimgo/wepush/model/SMSInfo.java b/src/main/java/com/kimgo/wepush/model/SMSInfo.java
index 18b1cce..674f7c9 100644
--- a/src/main/java/com/kimgo/wepush/model/SMSInfo.java
+++ b/src/main/java/com/kimgo/wepush/model/SMSInfo.java
@@ -1,15 +1,19 @@
 package com.kimgo.wepush.model;
 
+import com.kimgo.wepush.controller.SMSController;
 import io.micrometer.common.util.StringUtils;
 import lombok.Getter;
 import lombok.Setter;
 import lombok.ToString;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 
 @Getter
 @Setter
 @ToString
 public class SMSInfo {
+    private final Logger logger = LoggerFactory.getLogger(SMSInfo.class);
     private String smsNumber;
     private String smsAcceptanceTime;
     private String smsContent;
@@ -24,4 +28,12 @@ public class SMSInfo {
                 StringUtils.isNotBlank(smsAcceptanceTime) &&
                 StringUtils.isNotBlank(smsContent);
     }
+    public boolean isNullString(){
+        String nullString = "null";
+        if (this.smsNumber.equals(nullString) || this.smsContent.equals(nullString) || this.smsAcceptanceTime.equals(nullString)){
+            logger.info("SMSInfo has null String.");
+            return false;
+        }
+        return true;
+    }
 }
\ No newline at end of file