In the simulation of laser turbulence propagation, with the continuous enhancement of turbulence along the path, the light spot will produce huge distortion, and it is often impossible to have high simulation accuracy and computational efficiency at the same time. In this paper, a method is proposed to simulate the laser propagation in moderate-strong turbulence channel by adopting different sampling mesh spacing in the transmitting and receiving plane. This method can be used to set up different mesh spacing between the transmitting and receiving planes according to the specific situation while keeping the number of sampling points unchanged, to make the simulation results of laser propagation closer to the theoretical value at various turbulence intensities. The simulation results show that, after the mesh spacing of transmitting plane is reduced, the relative error of scintillation index simulation value decreases from more than 20% to less than 10%, and the minimum error reaches 4.15%. The standard deviation of scintillation index simulation value also decreases from more than 0.07 to less than 0.05, and the minimum error reaches 0.015.