In early electric vehicles(EVs) and hybrid electric vehicles(HEVs), the on-board power management strategy controlled the state of charge of the battery. However, in modern EVs and HEVs, the purpose of a strategic power and energy management system is to control and coordinate the power generation, energy storage, and power flow within subsystems to achieve maximum overall system efficiency. In this paper, we use the equivalent consumption minimization strategy(ECMS) to achieve energy and power efficiency of the parallel plug-in hybrid electric vehicle(PHEV). The ECMS is a heuristic method to address the optimal control problem. Also, it provides an effective solution to the PHEV energy management problem