Aiming at the complicated and changeable channel of seawater laser communication channel, Monte Carlo simulation is used to simulate the transmission process of blue green laser in seawater channel, and the simultaneous interpreting of the received power under different transmission distances is obtained. The Gauss function and arc fitting algorithm are used to fit the statistical results respectively. The Gauss fitting error and the arc fitting error of the laser in different distances are calculated. The fitting error of the arc algorithm is less than that of Gauss function fitting. Based on the arc fitting algorithm, the underwater wireless optical communication channel model is established. According to the transmission model, the relationship among laser transmission distance, arbitrary receiving position and receiving power can be quickly obtained under certain sea water quality parameters, which provides reference value for the design of underwater wireless optical communication system.