本文从洞窟相关遗迹出发,结合佛教典籍和史料,认为擂鼓台区第4窟是武周时期开凿的皇家洞窟,窟内外雕刻的“一万五千佛”是礼忏之用,突出于其外的弥勒像则服务于武周革命合法性的舆论再营造,壁面底部《付法藏因缘传》相关经、像所营造的“末法”氛围为弥勒像的出现做了自然的铺垫;洞窟开凿的背景一是武则天对其长期以来滥杀行为的忏悔,二是为武周革命合法性的再鼓吹,整个洞窟造像内容的设置正是这样背景的产物。 In this paper, starting from the cave-related relics, combining Buddhist books and historical data, it is considered that the 4th cave in Leiguqqetai is a royal cave excavated in the period of Wu and Zhou Dynasties, and “15,000 Buddhas” engraved inside and outside the cave are used for ceremonies. On the other hand, the Maitreya image served as a media re-creation for the legitimacy of the revolutionary revolution in Wu-Zhou. The relevant book of “Paying for Dharma-related Genesis in the Dharma-possession” at the bottom of the wall made a natural groundwork for the appearance of Maitreya The background of the cave excavation was that of Empress Wu on his penitence for a long time and on the other hand the re-advocacy of the revolutionary legitimacy of the Wu-wu revolution. The setting of the content of the caves like this is the product of such a background.