Abstract: By analyzing the measure data of the Sakyamuni pagoda in Yingxian County, Shanxi Province, a new measure regulation was put forward based on the former viewpoints. According to the new measure regulation, the change in the side length of each span of each story can be further explained. The research shows that the measure regulation of this Sakyamuni pagoda is a modulus system, and the basic modulus is 22.1 cm to control the height and the side lengths of each story and each span. Based on the basic modulus, the side lengths of each story and each span have a gradually changing and simple regulation. This phenomenon is similar to that of some ancient pagodas in the periods of Asuka and Nara in Japan and can be used as an important evidence to the existence of a modulus system in ancient buildings in the period from the Tang Dynasty to the Song Dynasty.