首先以root账户登录命令行
Enter password: **************
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 384
Server version: 5.0.51b-community-nt-log MySQL Community Edition (GPL)
Type 'help;' or '\h' for help. Type '\c' to clear the buffer
//就下面这一行而已，把单引号里面的内容改成自己的新密码，OK.
mysql> set password = password('newpassword');