您可以创建一个助手函数，该函数每年仅返回一次年份号：

function get_unique_year( $post_id = 0 )
{
    static $last = 0;

    $post_id || $post_id = get_the_ID();

    $year = get_the_time( \'Y\', $post_id );

    if ( $year === $last )
        return;

    $last = $year;

    return $last;
}

$posts = wp_get_recent_posts(); // or any other function returning posts

foreach ( $posts as $post )
    if ( $year = get_unique_year( $post->ID ) )
        print "Year: $year<br>";