The development of alternative energy-propelled vehicles has taken off as traditional energy sources become scarcer. In this study, a lithium battery management system is designed in terms of hardware circuit and algorithm control. A battery State of Charge (SOC) detection method based on Adaptive Weighted Least Square (AWLS) estimation is proposed. The method can accurately reflect the current battery capacity, and based on this, the equalization charging method is adopted to monitor and protect the electric safety of electric motorcycles in real time and prolong the service life of the battery. Finally, the experiment shows that the battery pack voltage acquisition error is less than 1% and the SOC estimation error is less than 4%, which is lower than the estimation error of the ampere-time integration method. These results show that the battery management system's SOC measurement method and charging/discharging strategy have a positive impact on the electric motorcycle's range and battery life.