It is difficult to analyze the transmission error of the planetary gear system in the wind power gearbox during its operation. In order to solve this problem, considering the actual working conditions of the planetary gear system, a nonlinear multi-gap planetary gear system finite element model was established by using 3D drawing software. Explicit dynamic solution method was used, and combined with nonlinear dynamics software and gear meshing principle, the variation laws of dynamic transmission error curve of wind turbine planetary gear system under different speeds and loads were discussed. The results show that there is a certain correlation between timevarying meshing stiffness and dynamic transmission error; the dynamic transmission error of the planetary gear system is different from that of the planetary gear. The simulation results show that the gear meshing stiffness and transmission error have influence on the operation 〖JP2〗process of the planetary gear system in wind turbine gearbox, and trimming gears should be used in practical application.