自己解決しました。
同じサーバー内であれば、1つのデーターベースから複数なWordpressに情報をひっぱることができます!
難しくないです。
こちらがソースです。
<?php
//その他DB接続設定
$another_db_user = 'user';
$another_db_pass = 'pass';
$another_db_name = 'name';
$another_db_host = 'localhost';
$another_tb_prefix = 'wp_';
$mydb = new wpdb($another_db_user,$another_db_pass,$another_db_name,$another_db_host);
$mydb->set_prefix($another_tb_prefix);
//SQLでデーターベースに直接アクセスして、情報をとる
$result = $mydb->get_results("
SELECT
m0.post_title,
m0.id,
m0.post_name,
m0.guid,
(select m1.meta_value from wp_postmeta m1 where m1.post_id = m0.id and m1.meta_key = 'association' ) AS 'association',
(select m2.meta_value from wp_postmeta m2 where m2.post_id = m0.id and m2.meta_key = 'catchcopy' ) AS 'catchcopy',
(select m3.meta_value from wp_postmeta m3 where m3.post_id = m0.id and m3.meta_key = 'name_furigana' ) AS 'name_furigana'
FROM ( select post_title, id, guid, post_name from wp_posts where post_type = 'bio' AND post_status = 'publish' ) AS m0
ORDER BY name_furigana ASC
");
//情報取得
foreach ($result as $value) {
$the_post_id = $value->id;
//アイキャッチ取得
$sql_for_eyecatch = "
SELECT meta_value
FROM $mydb->postmeta
WHERE post_id = (SELECT meta_value FROM $mydb->postmeta WHERE post_id = $the_post_id AND meta_key = '_thumbnail_id') AND meta_key = '_wp_attached_file'";
$eyecatch = $mydb->get_var($sql_for_eyecatch);
//表示される
print('<div class="profile-list"><a href="'.get_permalink( 115822 ).'/'.$value->post_name.'"><p class="image"><img width="300px" src="http://www.test.com/wp-content/uploads/'.$eyecatch.'" alt="'.$value->post_title.'" /></p><p class="position">テスト</p><div class="info"><p class="name">'.$value->post_title.'</p><p class="association">'.$value->association.'</p><p class="number">'.$value->catchcopy.'</p></div></a></div>');
}
?>