Abstract: Effects of high-frequency cyclic loading on tribological properties of inner spherical-surface contacting pairs between the differential gear end-face and shell washer of heavy vehicles, were experimentally investigated. The high frequency cyclic loads with different extreme amplitudes were produced by exciting different spring-connecting weights. The friction force signals were analyzed by Discrete Wavelet Transform method. And the wear process and wear scars of the thrust washers were observed. Research indicated that the low-frequency signal components of the friction force signals under high-frequency cyclic loading can be used to assess the friction state and the variation tendency. The cyclic loading with extreme amplitude tended to produce different severe wear forms, e.g. fatigue wear, plowing damages, material side flow and plastic deformation. And the excitation of large cyclic loading had a very significant influence on the tribological performance of the spherical-surface mating pairs and was apt to break the frictional stability of the sliding pairs. Therefore, reducing the force amplitude and lessening the excitation magnitude improved the tribological properties of spherical-surface mating pairs.