The paper studies concomitant motion kinematics. In kinematics , the kinematical relation of the relative motion between concomitant satellite and main satellite is deduced; the three applications of the kindematical relation are discussed. Supposing the main satellite orbit is circular. the concomitant motion equations with earth-fixed coordinate system and main satellite orbit-fixed coordinate system (in four cases) are deduced. Concomitant orbit shapes and characteristics are gained by analysis.