The invention discloses a modular multilevel converter (MMC) power module control protection closed-loop testing method. The MMC power module control protection closed-loop testing method comprises the steps that a simulation model of an MMC is established on a GTFPGA board card of an MMC real-time simulation device, wherein the simulation model comprises M a-class power modules and N b-class power modules; the a-class power modules transmit the capacitance voltage of the a-class power modules to M corresponding power module controllers through a PB5 board card and a GTAO board card, and thusthe capacitance voltage is transmitted to a pulse distribution screen through the power module controllers; the module state is transmitted to the power module controllers through the GTFPGA board card, and thus trigger communication signals of IGBTs of the power modules are transmitted to the a-class power modules through the power module controllers; trigger control signals of the a-class powermodules are transmitted to the power module controllers through the pulse distribution screen, and thus trigger signals output by the power module controllers are transmitted to corresponding controlbypass switches and bypass thyristors through a GTDI board card; the N b-class power modules conduct optical signal interaction with a valve control device through the Aurora communication protocol; and the valve control device is connected with an upper-layer control protection device to realize MMC power module control protection closed-loop testing.