This paper studies the hardware-in-the-loop (HiL) design of a power-split hybrid electric vehicle (HEV) for the research of HEV lithium-ion battery aging. In this paper, an electrochemical model of a lithium ion battery pack with the characteristics of battery aging, is built and integrated into the vehicle model of Autonomie® software from Argonne National Laboratory. The vehicle model, together with the electrochemical battery model, is designed to run in a dSPACE real-time simulator while the powertrain power is managed by a dSPACE MicroAutoBoxII hardware controller. The control interface is designed using dSPACE ControlDesk to monitor the real-time simulation results. The HiL simulation results with the performance of vehicle fuel economy and dynamics, the thermal aging of the battery are presented and analyzed. The research laid a solid foundation for the future work on HiL design of HEV control with the consideration of battery aging and the component-in-the-loop study of the lithium ion battery running in real-time.