您正在搜索的用户表列为user_email

$emails = new WP_User_Query( array(
    \'fields\'  => array( \'display_name\', \'user_email\', ), // you don\'t want everything, right?
    \'orderby\' => \'email\',                                // \'user_email\' works as well
    \'order\'   => \'ASC\',                                  // default: \'DESC\'
    \'number\'  => 10,                                     // total amount of users to return
    \'offset\'  => 0,                                      // use in combination with \'number\' to page results
    \'search\'  => \'*@*\',
    \'search_columns\' => \'user_email\',
    \'blog_id\' => get_current_blog_id(),                  // Multisite needs that, allows cross site search
    \'role\'    => \'subscriber\',                           // in case you want to exclude admins, etc.
    \'exclude\' => array( 1, ),                            // Blacklist user IDs
) );

<?php /* Plugin Name: Debug User Query */
add_filter( \'pre_user_query\', function( &$query )
{
    var_dump( $GLOBALS[\'wp_query\']->last_query );
    return $query;
} );