Abstract. In order to achieve the test of function and strategy of pure electric car vehicle control unit(VCU) better, this paper designs a hardware-in-the-loop (HIL) test system for VCU based on NI-PXI platform. Firstly, expounding the principle of HIL testing technology and introducing the HIL test system plan based on demand analysis, then making sure the hardware which is used by system, and using it to build a vehicle model with MATLAB/Simulink successfully, finally running tests on the HIL testing system to demonstrate the political legitimacy and viability of the system.