Abstract: Aiming at the high failure rate of wind power gearboxes,a way to calculate the transient performance of the wind energy gearbox’s planetary gear set under the recombination of the root crack and tooth surface friction is posited based on an analysis of the vibration response mechanism of the wind energy transmission system. Firstly,analyze meshing stiffness of gears containing root crack defects,considering different sliding friction factors. Subsequently,using the lumped parameter method,a dynamic response calculation model of the planetary gear system that considers the interaction of the two effects of translation and torsion is established. By accounting for the coupling of the root crack and the sliding friction,the model is used to simulate the effect of time-varying mesh stiffness on the planetary wheel system. The results show that the sliding friction between the tooth surfaces causes the low-frequency region of planetary gear torsional vibration to be suppressed and the intermediate frequency region to be enhanced. Tooth root cracking causes modulation effects in the system,resulting in modulation sidebands in the response of the torsional vibration spectrum around the meshing frequency between the planetary gear and the sun gear.