To evaluate the system dynamics and verify the control strategy for a plug-in hybrid electric vehicle (PHEV), this paper studied the techniques for developing a real-time PHEV simulator and a hardware-in-the-loop (HIL) platform. For PHEV modeling, a graphical program was constructed. Subsystems of a PHEV include: driving cycles, driver's behavior, the SI engine, the traction motor, the high-power lithium battery, the Integrated Starter Generator (ISG), the transmission, the longitudinal vehicle dynamics, etc. have been introduced and combined to form a complete PHEV model. Next, to verify the strategy of the Vehicle Control Unit (VCU), a HIL environment needs to be established. A host PC is utilized to download real-time models and supervising the chosen parameters. A target simulator operates the model in real time due to its superior computational efficiency. A rapid-prototyping controller executes the control strategy online to examine the accuracy and detect logical errors. Ultimately, the real-time PHEV dynamics as well as the VCU control strategy are able to be simulated in this PHEV HIL platform online.