In order to verify the accuracy of scattering phase function used in ocean optics in the simulation of key performance indexes of underwater wireless optical communication (UWOC) system, based on Monte Carlo method, the influence of five approximate phase functions on receiver bit error rate (BER) of UWOC system is studied by simulations in order to obtain the phase function model suitable for channel simulation and system performance detection under different water quality conditions. The results show that the Sahu-Shanmugam (SS) and Fournier-Forand (FF) functions have the least influence on BER simulation; the influence of Henyey-Greenstein (HG) and Two-Term Henyey-Greenstein (TTHG) on BER simulation is closely related to water types; and the BER simulation deviation caused by Haltrin function is the largest.