In order to perform technical identification and equipment testing of power electronic facilities, a method of active power filter (APF) controller closed-loop simulation based on real time digital simulator (RTDS) is presented. The primary circuit, including three-phase grid, load, inverter bridge of APF, DC-link capacitor and breaker, is simulated using the software provided by RTDS. The real control panel is used for the protection and control signal output. The standard interface board which composes of five different types of signal conditioners is employed to solve the signal matching problem between APF controller and the RTDS software model. The integrated simulation model is built in the RTDS' small-step environment and the core simulation modules, such as trigger pulse model of insulated gate bipolar transistor (IGBT), protection and control signal logic chart, short-circuit faults model and observing interface of RTDS are analyzed in details. These form the integrated test procedure and project for this research. Through the comparative analysis of the data between equipment test and controller closed-loop simulation based on RTDS, the method is validated. ©2014 State Grid Electric Power Research Institute Press