According to the demand of the micro-resistivity scanning tool test-bench, this paper proposes a design scheme of the test-bench communication interface program based on the C/S mode. From a comparison of the characteristics between the B/S and C/S communication modes and the flow and data report type sockets, the paper chooses the flow socket C/S mode as the mode of the communication interface. In order to solve the blocking problem of simple flow sockets, in the front-end computer, the multithreading technology is introduced to realize the independent communication process. In order to improve the interface scalability and portability, in the PC program, the Winsock control is used to realize the communication function. It is shown by performance tests that the communication interface has a good stability and speed. The interface enjoys features of simple structure, excellent performance and good portability, and can be directly applied in the test-bench and the testing system of similar structures.