这是密码-

function wpse_media_extra_column( $cols ) {
    $cols["alt"] = "ALT";
    return $cols;
}
function wpse_media_extra_column_value( $column_name, $id ) {
    if( $column_name == \'alt\' )
        echo get_post_meta( $id, \'_wp_attachment_image_alt\', true);
}
add_filter( \'manage_media_columns\', \'wpse_media_extra_column\' );
add_action( \'manage_media_custom_column\', \'wpse_media_extra_column_value\', 10, 2 );