Abstract: The cement filled artificial pillars are commonly use to replace the original pillars in room-and-pillar mining method in light with the deep-buried and short-span valuable metal ore body which is in horizontal or gently inclined. The analysis of the mechanical properties of cement filled artificial pillar reveals the temporal variation of mechanical behavior. The weight of rock stratum is worked out by the theory of PU's. Correspondingly, the strength theory of cement filled artificial pillar can calculate the width of the pillar. The width design of artificial pillar for deep mining by room-and-pillar method has great significance for mining design and production.