Abstract:The mechanical model of key strata supported by coal pillar is set up according to the layout of coal pillars in the coalface of short wall mining. With the help of analysis of elasticity and viscoelasticity of enforce and deformation of key strata using different design parameters in different working face,the theoretical formulas of ground subsidence of elastic medium key strata and the dependence of the deformation on time of viscoelastic medium key strata are obtained. The parameter ranges of the short wall mining under buildings are proposed;and the influence of key strata on the deformation with time for different parameters are evaluated. The model provides theoretical basis for the design of short wall mining under buildings,water bodies and railways,and for the prediction of ground subsidence.