Battery management system is the core equipment of electric vehicles and battery energy storage power station, which directly affect the performance of the battery pack, and then affect the safety and efficiency of electric vehicles and battery energy storage power station. The battery equalization technology is one of the core technology of battery management system. Several equalization technologies are introduced, compared and analyzed in this paper. Based on this, an active bi-directional equalization solution of battery pack is put forward. The principle of this equalization solution is expounded in detail in this paper, and the feasibility of the proposed solution is verified by MATLAB simulation experiments.