When the stator winding of asynchronous motor fails in the traction control system, the stator winding is asymmetrically connected, which seriously affects the safe and stable operation of the traction control system of electric locomotive. Aiming at the open phase of the stator phase winding of the asynchronous motor in the traction control system, considering the terminal voltage constraint, the mathematical model of the motor open phase circuit is derived, and the mathematical model is verified based on the hardware-in-the-loop (HIL) simulation test platform. The system framework, design and implementation method, hardware and software connection configuration of HIL test platform are described in detail. The motor open phase mathematical model built under Xilinx software is downloaded to the dSPACE simulator for operation, connected with the traction control unit (TCU), and the HIL simulation experiment is carried out. The motor open phase is judged and handled through the detection algorithm. The experimental results verify the effectiveness of the simulation test platform. In a near real test environment, a theoretical basis and design basis for the motor open phase diagnosis and algorithm function development of the traction control system is provided.