how to customized user login page
You can make a template to alter your user login form.

In template.php:

function YOURTHEMENAME_theme(){
    return array(
        'user_login' =&gt; array(
            'arguments' =&gt; array('form' =&gt; NULL),
            'render element' =&gt; 'form',
            'template' =&gt; 'templates/user-login-form',
        ),
  );
}


Then create user-login-form.tpl.php in your template folder and print the login form using

print drupal_render_children($form);


Don't forget to clear cache