This paper introduces the basic principle of stripe reflection method and proposes an improved algorithm on the traditional Southwell gradient iterative integration algorithm. The algorithm adds a coefficient value with an attenuation factor to the compensation height value and the value of the attenuation factor is changed by the determination of the compensation height threshold. Through computer simulation, the fitting error of the reconstructed surface show that the RMS of the new method is one order of magnitude better than the traditional algorithm and the PV value of the high frequency part is about 1/15 of the traditional algorithm. It is proved that the improved algorithm can effectively improve the convergence and noise resistance of the iterative algorithm.