This article introduces a Hardware-In-Loop test platform for electric vehicle Cell Battery Management System (BMS). At first, system structure of test method is projected to make requests for a battery emulator which is the main work of test platform. Then hardware is designed to simulate the input and output signals of BMS. The model for Lithium-ion battery, hardware driver and relative algorithm are built in Matlab/Simulink. After the model is validated, automatic code generation is performed. The code is downloaded to hardware platform. This platform enables validation of BMS instead of using real batteries.