Abstract: A control strategy based on fuzzy logic is proposed for a series hybrid electric vehicle.According to the stat-of-charge of batteries and the power required by the vehicle,the engine output power is real-time changed to realize constant SOC control,and the fuel consumption and emissions are considered as well.The architecture of the vehicle controller is given and a forward simulation model for the vehicle is established.Both off-line and hardware-in-loop simulations are performed.Simulation results show that the fuzzy logic control strategy can maintain the SOC of batteries nearby the exceptive value 0.7,and the engine works at its high efficiency area to get low fuel consumption and emissions.