帮我改下？？

你这是java吗？首先类名就搞错了的，类名首字母大写的哈！
import java.util.Scanner;

public class Title {
    public static void main(String[] args) {
        String username = "admin";
        String password = "123";
        Scanner input = new Scanner(System.in);
        System.out.print("请输入用户名：");
        String userName = input.nextLine();
        System.out.print("请输入密码：");
        String passWord = input.next();
        if (userName != null && userName.equals(username) && passWord != null
                && passWord.equals(password)) {
            System.out.println("欢迎你，" + username);
        } else {
            System.out.println("对不起，你不是" + username);
        }
    }

}