diff --git a/src/main/java/cactusServer/models/Accounts.java b/src/main/java/cactusServer/models/Accounts.java
index 42df1eb..5be7d51 100644
--- a/src/main/java/cactusServer/models/Accounts.java
+++ b/src/main/java/cactusServer/models/Accounts.java
@@ -37,8 +37,12 @@
 	}
 
 	public Account getAccount(String userID) {
-		Account editAccount = accounts.get(userID);
-		return editAccount;
+		if(idSet.contains(userID)) {
+			Account editAccount = accounts.get(userID);
+			return editAccount;
+		}else {
+			return null;
+		}
 	}
 
 	public Account loginAccount(String userID,String userPass) {
@@ -51,13 +55,22 @@
 	}
 	
 	public String logoutAccount(String userID) {
-		Accounts.getInstance().getAccount(userID).setLogin(false);
-		return "success";
+		if(idSet.contains(userID)) {
+			Accounts.getInstance().getAccount(userID).setLogin(false);
+			return "success";
+		}else {
+			return "null";
+		}
 	}
 	
 	public String deleteAccount(String userID) {
-		accounts.remove(userID);
-		return "complated remove account";
+		if(idSet.contains(userID)) {
+			accounts.remove(userID);
+			idSet.remove(userID);
+			return "complated remove account";
+		}else {
+			return "not exist";
+		}
 	}
 
 }