Abstract: By analyzing the temporal and spatial evolution law of mine pressure in the course of mine-like paste filling mining, the load-bearing evolution mechanism and characteristics of the temporary coal pillars and the filling body in the course of "mining-filling" are explained, Get the requirements for the ultimate strength of the backfill. Based on this, using the coal pillar strength theory and the empirical formula of the development height of the fracture zone, the reasonable range of the temporary coal pillar width, the development height of the fracture zone and the ultimate load of the filling body are calculated. Finally, the strength of the backfill was checked, and the width of the temporary coal pillar was verified and optimized by numerical simulation, and finally a reasonable width of the temporary coal pillar was determined.