An attitude tracking control algorithm was designed for the problem of attitude synchronization control during on-orbit servicing spacecraft approaching and capturing out-of-control target.The control problem of servicing spacecraft tracking out-of-control target spacecraft’s attitude was converted to the relative attitude control problem by establishing the relative attitude kinematics and dynamics of servicing spacecraft with respect to out-of-control target.Considering the factor of unknown disturbances and limited control torque,and the relative attitude dynamics was expressed as two-order equation of relative attitude quaternion,utilizing the feedback linearization theory and the thought of adaptive algorithm,a nonlinear feedback control law for attitude synchronization was designed.Numerical simulations have demonstrated the effectiveness and good tracking performance of the designed control algorithm.