Abstract: Energy management strategy (EMS) is critical to improving the fuel economy, protecting the health status, and reducing the greenhouse gas emissions of hybrid electric vehicles (HEVs). However, due to the complex nonlinear structure of the power system and the real-time requirements of online applications, it is still a challenge task to develop an efficient EMS. Therefore, the evolution of energy management technology was summarized completely in this paper. Firstly, the electro-mechanical coupled systems used widely in HEVs and their topological structures and functional features were surveyed. Secondly, the research progress and development trend of EMS were analyzed synthetically. In addition, the technical advantages and disadvantages of various methods were evaluated based on fundamental technical indicators such as optimality and real-time performance, providing a reference for further engineering applications. Finally, the future research trend of EMS was prospected, hoping to provide a reference for the development of EMS under the intelligent connected environment.