The communication module of subway electrical cabinet logic tester is researched and designed in this paper. The communication module of subway cabinet logic tester contains two parts: the communication between system layer and management layer, the communication between management layer and testing layer. In the cabinet logic tester, the communication between system layer and management layer has large amount of data and high frequency, so CAN bus is used, at the same time, the communication between management layer and testing layer doesn't have the problem of distance and has small amount of data, so RS485 is used. On the basis of hardware design, communication software is designed. According to site commissioning, the communication module designed enables reliable communication between systems.