Aiming at the problem of high cost and slow equalization speed in traditional circuit, a parallel filling valley equalization circuit based on fuzzy control is proposed in this paper. A fuzzy controller suitable for the circuit is designed. The average voltage, voltage range and the balance electric quantity of the battery pack are modeled by fuzzy model. The fuzzy reasoning and defuzzification is produced to optimize the circuit control logic, which can be adapted to the nonlinearity of the battery pack and the uncertainty of the battery parameters. The simulation and experiment results show that, in the process of charging and discharging, the fuzzy control based parallel filling valley equalization circuit has the advantage of fast and efficient equalization which can improve the use efficiency of the battery pack.