To prevent energy control system from mistaking switching during its operation mode for seriesparallel hybrid electric vehicle (HEV) when interfered, a mixed sensitivity H∞robust controller was developed. Weighted functions were determined based on genetics arithmetic. Compared with the PID controller under step response, the mixed sensitivity H∞robust controller reduced the settling time by 41.3% and overshoot by 14.7%. It also could keep energy control system stable under the two factors of uncertain parameters and external interference. Mistaking switching operation was restrained effectively and more smooth driving performance was acquired. 