The invention discloses a flexible direct current FT3 message template library formation method. The method comprises the steps that a communication protocol, that is, channel mapping information, between flexible direct current protections is acquired, and a software part of a flexible direct current test system provides a standard FT3 template file; according to the flexible direct current protection FT3 communication protocol, parameter information such as the channel number is manually modified in the template file, channel mapping between voltages and currents and switching values is conducted, and after mapping is finished, the template file can be saved as an engineering application template file; and the flexible direct current protection test system loads the engineering application file and then can conduct communication loop verification work on a flexible direct current protection device. According to the method, different flexible direct current protection manufacturers and different flexible direct current converter station digital FT3 message template libraries are formed, manual configuration of the message template libraries is supported, and a technical support isprovided for later flexible direct current converter station maintenance and updating.