Abstract A contact trajectory model of ball bearings under the dynamic condition was developed by the means of the development of the integrated multi-body dynamics and multi-freedom kinematics with the multi-interfacial contact mechanics. Subsequently, the general methodology was employed to investigate the dynamic contact performance of ball bearings, particularly for the contact trajectory along the raceways due to each ball against the inner and outer raceways. It was found that the radial loading and inner ring misalignment could lead to the deviation of the contact trajectory on the raceways. The variation of contact angle could bring into the correspondence with the deviation of the contact trajectory on the raceways. The oscillation frequency of the contact trajectory on the outer raceway was higher than one on the inner raceway either under the axial and radial loading or misalignment condition.