Taking the NGW planetary gear train in the hub reducer as the research object,a 10-degree-of-freedom dynamic model considering tooth surface friction is established,and the dynamic equation is derived.The contact force between gears was obtained through ADAMS simulation,and the influence of floating structure,input speed,load,and friction coefficient on the load sharing characteristics of the planetary gear system with or without tooth surface friction was analyzed.The results show that,regardless of tooth surface friction,the double floating structure is better than the other two structures;the system load sharing factor increases with the increase of the input speed,decreases with the increase of the load,and changes slightly with the increase of the friction coefficient.