Abstract: The estimate of mining subsidence is one of the core contents on surface subsidence discipline,and it has great practical significance on buildings and ecological environment protection.The paper simulates working face of the typical shallow coal seam by the UDEC,even analyzes the coupling effects of topsoil and main key stratum to surface subsidence through setting up four models.Under the condition of thin topsoil thick and hard key stratum,it will be drew the conclusion that the coupling effect of topsoil and main key stratum must be considered on the estimate of mining subsidence.