Abstract: The seam mining problems of different width,different bedrock height,different lithological characters of working face advancing are simulated by using PFC^2D particle flow software,and the general laws of overburden failue are obtained.Comparing the conclusions derived from theoretical analysis of damage mechanics with numerical simulation results,two results are consistent,which shows that the conclusion of this paper is feasible,effective and contribute to solve the problems encountered by the coal seam mining under the thin bedrock,which provides a reference for safety and stability production of mine.