Abstract: A method of measuring the atmospheric turbulence based on the arrival angle fluctuation of a focused laser beam backscattering was numerically simulated. Based on the paraxial scalar wave equation and a fractal phase-screen algorithm a simu-lation model for the focused laser beam propagating along a fold path was proposed. With a constant Fried length, the arrival angle fluctuation variance was analyzed between the focused laser beam backscattering and the fixed point-source as reference beacon. A relatively high correlation between them was obtained. The simulation results were verified by experimental data.