A real time digital simulator (RTDS) testing method of a fault current limiter belongs to the field of emergency protecting circuit devices. RTDS analog quantity signals are sent by an RTDS testing device and used for simulating fault signals in an actual operation process. The RTDS analog quantity signals pass through a power amplifier to be output to a measuring system of a fault current limiter (FCL) control protecting system. The measuring system conducts signal processing on the input analog quantity signals and sends the analog quantity signals to an analog-to-digital (AD) conversion module in the measuring system, and results obtained after AD conversion are packaged and transmitted to the FCL control protecting system through optical fiber. Interacting of logic signals between the FCL control protecting system and the RTDS testing device is achieved through an input/output (I/O) port in an RTDS real time simulation test. The RTDS testing method of the fault current limiter can be widely applied to the fields of designing and testing and the like of a control and protecting strategy of the FCL control protecting device.