Abstract: A cooling system for a Stirling engine which includes a cooler, an ultrasonic wave generator for making cooling fluid into atomized particles, a water tank, a pump and an electric power generator for generating electric power by driving force of the Stirling engine to supply the electric power to the pump and the ultrasonic wave generator, whereby the cooling fluid is converted to atomized particles of cooling fluid and then phase changing latent heat generated by the process of changing the atomized particles of cooling fluid to gas is utilized so that working fluid of Stirling engine is effectively cooled.