Abstract: On the basis of studying the characteristics of electric power battery and its relevant charging strategy, the article developes the double closed-loop charge-control system based on EG3525, and gives structure and realization method of the circuit. By utilizing the single-chip computer and MAX11068 voltage acquisition chip, the system completes charging control and data display, can measure battery voltage, current and control the battery state of charge and discharge real-timely and reliably, and protect the battery upmostly and improve the stability of the direct current supply.