In view of the lack of design and research of the gearbox for high power wind power growth gearbox,a 5 MW-level design scheme was put forward,and the dynamics analysis was carried out.Three-stage transmission type was adopted,the first two stages were 2KH type planetary gear train,and the third stage was fixed axis gear train.Simulation analysis and theoretical calculation results were compared through the input wind power load spectrum to ensure the accuracy of the calculation results.Using the dynamic method,the modal analysis of the planetary frame was carried out to make the modal frequency of the planetary frame avoid the meshing frequency of the gears;the transmission error of each gear pair was analyzed,and the periodic variation rule of the transmission error of each gear pair and maximum error were obtained;by analyzing the acceleration response of each bearing,the vibration acceleration curves at different speeds were obtained,and the law that the crest and trough of the acceleration curves of each bearing overlap was found,which made the input speed of gearbox avoid the peak.It provides method for the design and reliability analysis of high power wind power gearbox.