Abstract: The principle of stochastic parallel gradient descent (SPGD) algorithm is introduced, and the algorithm flow is verified through simulation. Two critical factors, the stochastic perturbation and the gain coefficient, are especially analyzed. The simulation results show that there is a most appropriate interval for selecting the two factors. Only with the two factors selected in this interval, the algorithm can achieve the best convergence value. Based on the simulation results, the coherent beam combining experiments are carried out with fiber lasers, resulting in significant effect of beam combining. The experimental results prove the results of simulation above. In conclusion, the research results would improve the design of coherent beam combining experiments for high power laser in the future.