Digital physical hybrid simulation is a new technology in today’s power system simulation, and the interface is the core of the hybrid simulation technology. Power interface design for the hybrid real-time simulation of the RTDS and physical model is carried out, and the characteristics of hybrid simulation interface are studied. Technical route for four-quadrant amplifier interface is put forward, therefore the key technical problems of the hybrid simulation interface are solved, and hybrid simulation interface established. Through the hybrid simulation tests of passive physical model and active physical model, and respectively comparing with the pure digital simulation results, the accuracy and stability of the interface are verified. The result provides a reference for the practical application of the hybrid simulation.