第一步：用帐号登录mysql
[root@CentOs5 ~]# mysql -u root

第二步：改变用户数据库

mysql> use mysql

Reading table information for completion of table and column names

You can turn off this feature to get a quicker startup with -A

Database changed

第三步：修改密码，记得密码要用password()函数进行加密，一定不要忘记！！！
mysql> 

update 

user 

set 

password=password('qwe123') where 

user='root';

Query OK, 1 row affected (0.04 sec)

Rows matched: 1  Changed: 1  Warnings: 0

第四步：刷新权限表

mysql> flush privileges;

Query OK, 0 rows affected (0.00 sec)

第五步：退出mysql
mysql> quit

Bye

第六步：对mysql进行重启
[root@CentOs5 ~]# service mysqld restart;

STOPPING server from pid file /var/run/mysqld/mysqld.pid

100421 13:44:03  mysqld ended

Stopping MySQL:                                            [  OK  ]

Starting MySQL:                                            [  OK  ]

[1]+  Done                    mysqld_safe –skip-grant-tables