Disclosed is a cooling device for a turbine nozzle guide vane with a low-melting-point metal as a flowing working media. A plurality of cooling channels and a cavity are arranged in a guide vane. The cooling device includes a flow divider, a collector, a radiator and an electromagnetic pump, the cooling device and the guide vane form a closed loop. Liquid low-melting-point metal or alloy thereof as the flowing working medium is driven by the electromagnetic pump to circularly flow in the closed loop and dissipate rapidly through the radiator. Air cooling is not adopted in the present disclosure, cooling air originally led out from a gas compressor is saved so as to increase the propelling power of an aircraft. Air film holes do not need to be formed in the outer surface of the guide vane so as to improve strength of the guide vane.