diff --git a/src/main/java/cactusServer/models/Accounts.java b/src/main/java/cactusServer/models/Accounts.java
index a70293f..5be7d51 100644
--- a/src/main/java/cactusServer/models/Accounts.java
+++ b/src/main/java/cactusServer/models/Accounts.java
@@ -11,7 +11,7 @@
 public class Accounts {
 	private static Accounts theInstance = null;
 	private HashMap<String, Account> accounts = new HashMap<>();
-	private HashSet<String> idList = new HashSet<String>();
+	private HashSet<String> idSet = new HashSet<String>();
 
 	private Accounts() {
 
@@ -26,7 +26,7 @@
 
 	public Account createAcount(String userID, String userName, String userPass) {
 		System.out.println(userName);
-		if(!idList.add(userID)) {
+		if(!idSet.add(userID)) {
 			return null;
 		}
 		Account newAccount = new Account(userName, userPass);
@@ -37,12 +37,16 @@
 	}
 
 	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) {
-		if(idList.contains(userID) && getAccount(userID).getPass().equals(userPass)) {
+		if(idSet.contains(userID) && getAccount(userID).getPass().equals(userPass)) {
 			Accounts.getInstance().getAccount(userID).setLogin(true);
 			return getAccount(userID);
 		}else {
@@ -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";
+		}
 	}
 
 }