Abstract: In order to realize the efficient transmission and state monitoring of the operation instructions of the self-developed micro combined EDM machine tools, a scheme of heterogeneous network interconnection is proposed, which uses "PCI_CAN + industrial computer "as the hardware platform realizes the data transmission of CAN bus system and the communication design of TCP end, analyzes the Socket principle, and uses the CAsyncSocket class in MFC to complete the establishment of Server/Client model. On this basis, by analyzing the communication service protocol between the client and the server and the CAN data frame user protocol, the conversion of the two protocols and the monitoring of the transmission information are realized on the server. The software has the function of detecting the status of each module of the system at the same time. The feasibility and correctness of the scheme are verified by software testing and debugging.