Aiming at the serious engineering problem on fretting wear of aviation spline, the influences of various factors on the stress and fretting wear of spline pair and the differences of intertooth space were studied. A fretting model of involute spline pair based on the fretting wear mechanism was established and it was verified by comparing the engineering test data. Through different loading methods, the influences of different loads on the spline pair of the helicopter reducer were studied and analyzed, and the influences of the fretting amplitude, dynamic load factor and the axial misalignment on the stress distribution and fretting wear of the spline transmission were analyzed comparatively. In the simulation results, the effect mean square value of the speed load was much larger than that of the torque load. The fretting amplitude was between 20 μm and 80 μm, the dynamic load factor was between 1.0 and 1.5, and the axial misalignment was between ?0.05 mm and 0.05 mm. The contact stress and fretting wear increased as various factors increased. The contact stress and fretting wear near the spline teeth root in the meshing area were the largest. Axial misalignment in different directions had different effects on the intertooth space, especially the spline with 6~9 and 15~18 teeth. The research results show that in spline transmission, the influence of the transmission speed on stress is greater compared with the transmission torque; the stress concentration and fretting wear near the spline teeth root in the meshing area are more serious; the fretting amplitude, dynamic load factor, the axial misalignment are positively related to the fretting wear and the axial alignment of the spline pair can decrease the influence of axial misalignment; there are differences in stress and fretting wear among different meshing areas and intertooth space.