On the lintel of the Zixiao Hall hangs a plaque inscribed with the words "Yunwai Qingdu". Qingdu, which is known as the Celestial Realm in Taoism, refers to the place where the Three Pure Ones resided and also the highest fairyland where immortals lived. "Yunwai Qingdu" is a compliment to the high rank of Zixiao Palace, which is like a fairyland of the Three Pure Ones above the Three realms. At the same time, it also praises the poetic and picturesque environment of Zixiao Palace, which is like a fairyland on earth.