The traditional equalization circuit which deals with the transfer of energy between adjacent cells is popular used in lithium battery pack. Nevertheless, this equalization circuit is inefficient. In order to improve the efficiency of equalization, an active equalization circuit based on flyback converter was proposed. The proposed circuit included four equalization modules. In each equalization module, energy from an overcharged cell or cells was stored temporarily in a coupling inductor, and then discharged into an uncharged cell or cells. The proposed active equalization circuit was simple, more efficient, and easy to control. To verify the proposed equalization circuit, compared with traditional multi-inductance equalization circuit and double-layer Buck-Boost equalization circuit, the topology was conducted in MATLAB / Simulink. The results show that the proposed equalization circuit has high efficiency and can achieve higher accuracy, which can effectively improve the equalization speed and shorten the equalization time.