With the expansion of power grid interconnection and the access of a large number of power electronic devices, in order to fulfill the need of analysis requirements of complex power system simulation after power electronic equipment accessing, it’s shown that adopting hybrid simulation of combining electromechanical transient simulator and electromagnetic transient simulator can solve the scale, velocity and calculation precision of system simulation. The developmental history and current situation of electromechanical-electromagnetic transient hybrid simulation are discussed and the existing domestic and foreign hybrid simulation platforms are comprehensively summarized. On this basis, the interfacing technology of hybrid simulation is discussed in four aspects:equivalent model, data conversion, interfacing location selection and interaction sequence. The connotation, technological difficulties and main problems of each aspect are introduced. Finally, this paper proposes the probable development direction and relevant problems of hybrid simulation technology in future. This work is supported by National Natural Science Foundation of China (No. 51307126).