您可以使用此代码，

$args = array(
    \'cat\' => 4, // Category ID
    // \'category_name\' => \'staff\', // Category Name
    \'posts_per_page\' => -1,
)

// The Query
$query = new WP_Query( $args );

// The Loop
while ( $query->have_posts() ) {

    $query->the_post();

    $thumbnail_image = get_post_meta( get_the_ID(), \'thumbnail_image\', true );
    $first_image     = get_post_meta( get_the_ID(), \'first_image\',     true );
    $second_image    = get_post_meta( get_the_ID(), \'second_image\',    true );
    $third_image     = get_post_meta( get_the_ID(), \'third_image\',     true );
}