Abstract: Smooth Particle Hydrodynamics(SPH)method was employed to model gas seepage in coal seam. Focused on the problem of transient seepage of gas in heterogeneous coal seam,a gridless SPH model was built by using Fortran program solving the variable coefficient partial differential equation of gas seepage,and through the virtual particle method dealing with boundary condition. The errors of constant coefficient seepage equation under different original gas pressures and permeability coefficients were analyzed. The change laws of gas pressure and gas emission quantity were obtained in heterogeneous coal seam with different permeability coefficients because of mining pressure and Weibull distribution. Simulation results show that the gas seepage in coal seam can be simulated efficiently by SPH method. The heterogeneous coal seam with different permeability coefficients because of mining pressure and Weibull distribu- tion will lead to the nonlinear flow of gas.