A battery power management system including a protection switch, a battery set, a high-voltage protection chip, a plurality of voltage-dividing units and a low-voltage measurement chip is provided. The protection switch and the battery set are connected in series between a first power terminal and a second power terminal of the battery power management system. The battery set includes a plurality of battery cells and has a plurality of sensing nodes. The high-voltage protection chip controls the protection switch according to a plurality of first sensing voltages from the sensing nodes. The voltage-dividing units are connected to a part of the sensing nodes and divide a part of the first sensing voltages to generate a plurality of second sensing voltages. The low-voltage measurement chip is connected to the voltage-dividing units and measures electric quantities of the battery cells according to the second sensing voltages.