The dynamic unbalance of the GyroWheel rotor will cause the jitter in the tilting motion and reduce the stable pointing precision of the spacecraft. In order to identify the couple unbalance of the rotor under the condition of anisotropic stiffness， an improved full vector dynamic balancing method is proposed. Firstly， the dynamic model of the GyroWheel is established according to the Lagrange equation. The transfer function between the two-axis tilting angle responses is derived using the complex coefficient method， and the response characteristics with unequal damping of inner and outer torsion bars of GyroWheel rotor are analyzed. Secondly， considering the nonlinear relationship between the phase angle of the characteristic vector of the elliptical trajectory and the phase angle of the unbalanced excitation， the equivalent vibration vector is constructed by using the forward precession component of the ellipse and based on the energy equivalence principle. In addition， the phase shift circle is constructed by the pure trial weight response. The dynamic balance algorithm based on the equivalent vibration vector and phase-shifting circle is given. Finally， the identification of couple unbalance is carried out in the simulation， and the correction is completed on the test platform. The numerical and experimental results show the effectiveness of the proposed method.