With the development of new energy technology and the proposition of the concept of smart grid, the structure and operation mode of distribution network are becoming more and more complex, and the digital-analog hybrid simulation technology has become the key technology to study complex distribution network. Aiming at the problem that the interface delay of the power hardware-in-loop (PHIL) digital-analog hybrid simulation system affects the stability and accuracy of the system, an improved simplified simplified current damped impedance method interface model is proposed in this paper, and the adaptive impedance matching algorithm is used to compensate the delay of the interface model, which realizes the real-time impedance tracking matching and improves the stability and accuracy of the hybrid simulation system. The proposed interface algorithm is verified by building a digital-analog hybrid simulation model of complex distribution network in RT-Lab real-time simulation platform