Abstract: To meet the development needs of modern power system real-time simulation, digital analog dynamic analog hybrid simulation combines the advantages of real-time digital simulation and physical dynamic simulation, and becomes an important simulation method for modern power system research. The interface system is the core and difficult part of the hybrid simulation system design. In order to deeply analyze the stability of the hybrid simulation system, the open-loop transfer function of the system was obtained by modeling each component of the interface system. The effects of different parameters in the open-loop transfer function on the stability of the system were studied according to the Rouse criterion and the Nyquist criterion, respectively. Theoretical derivation shows that the filter cutoff frequency, interface delay and impedance simulation ratio in the interface system have a large impact on the stability of the system. The experiments were conducted by the built hybrid simulation system, and the experimental results show that the influence of different parameters on the stability of the system is consistent with the theoretical derivation.