The Tang dynasty treasures uncovered from the basement of the Famensi Pagoda include quite a few relics that have something to do with Buddhist Mystic Sect. Some scholars believe that the whole of basement was rendered as a mandala. The author’s view is different, as he sees no affinity between the two either in theological or architectural terms. The basement was actually built after the pattern of a royal mausoleum, perhaps due to its designer’ s equation of the Buddhist founder with the ruler of mundane world. The casket for Sakyamuni’s relics enshrined in the rear cell is engraved with a grand mandala. There is no wonder about this, because the monk who took care of interment of the relics came from the Grand Xingshan Temple, the leading center of the Vajradhatu school of the Buddhist mystic sect. He must have arranged the cell in total compliance with the idea and protocol of, resulting in its difference from other rooms where the religious and secular, the mystic sect and manifest sect, are found together.