This paper proposed a new Chaos-Genetic Algorithm, which improved the combination between the chaos mapping and genetic algorithm in order to add chaotic search to the population evolution, so that the ergodicity of the genetic algorithm can be enhanced. And the algorithm can effectively overcome the defects of local optimum of the genetic. In the software ADVISOR2002, for a Plug-in Hybrid Electrical Vehicle (PHEV) using fuzzy energy management strategy as the research object, the membership functions and rules of fuzzy EMS were optimized with Chaos-Genetic Algorithm. Simulation results demonstrate that this Chaos-Genetic Algorithm can optimize the fuzzy EMS globally. Compared with the original fuzzy control strategy, the optimized fuel economy increases by 5.15% and the CO emission reduces by 6.39%.