The paper proposes a novel strategy of unloading momentum wheels utilizing momentum wheels aerodynamic torque for satellites with orbit below 500km, based on the character of the space environment torque. Unloading is completed by multiplexing the existing mechanism without any new mechanism. The electromagnetic interference and attitude tremble introduced by magnetic torquer unloading are reduced greatly. The proposed strategy can be used separately or used with other unloading strategies as backup, which has significant importance in engineering. Simulation results show that the proposed strategy works well without impacting satellite performance.