Mathematical representation of major parts of plug-in hybrid vehicle (PHEV) such as engine, motor, batteries, automatic clutch and vehicle body are made with analysis of configuration of PHEV. Specifications of data input and output and signal characters are defined. Hardware in the loop (HIL) system based on MATLAB/xPC for PHEV is built up. Take the case of motor/engine driving shift control logic test of PHEV is carried with inputting real acceleration pedal data. Testing results show that automatic clutch acts abnormally. Bugs in control logic are found out. Road test results with revised control logic are very good.