This paper takes a gas-electric Hybrid Electric Bus (HEB) equipped with compressed natural gas (CNG) engine as the research object. According to the measured operating conditions, the torque distribution of HEB is optimized using instantaneous equivalent fuel consumption algorithm. The torque command of the engine is built in the lookup table, and the logic threshold control strategy of torque distribution and command lookup table are combined to obtain the optimal torque distribution strategy. Simulation results show that the proposed control strategy can control the hybrid system working in the efficiency area effectively in the prerequisite of real-time performance, and can better maintain the balance of battery SOC and improve fuel economy of the HEB significantly.