Abstract: Taking the internal and external spline wear as an example, according to the observation of wear fracture morphology, it is determined that the wear of spline teeth is mainly caused by different axes of internal and external splines. A formula for calculating the sliding speed and friction work of spline teeth is presented. According to this, the influence of eccentricity, normal force, friction factor and tooth number on spline wear is comprehensively analyzed. The results show that the different axes of the internal and external spline shafts are one of the main reasons for the spline wear; the different axes of the internal and external spline shafts (the axis eccentricity) make the tooth surface of the key tooth slide; the eccentric axis makes the load distribution of each key tooth surface uneven, and accelerates the tooth surface wear; to prevent the spline tooth wear, the most effective measure is to increase the axis eccentricity The machining accuracy and installation accuracy of the parts can reduce the eccentricity of the internal and external splines as far as possible, and improve the hardness of the spline can increase the wear life of the spline.