This paper firstly introduces the principles of Stirling heat engines based on refrigerant phase-change circulation. This heat engines use two external heat reservoire. When the refrigerant in an engine cylinder absorbs heat from high-temperature heat sources, refrigerant is transformed from liquid to gas and the volume of the refrigerant expands to drive the piston apply work. When the refrigerant releases heat to low-temperature sources, the volume of the refrigerant shrinks. Therefore, phase change thermal engine technology using solar energy, industrial waste heat and heat produced by combustion of any fuel to work, no gas emissions, high thermal efficiency and environmental advantages. Thermal phase transition and thus the engine technology will be in the field of energy and power of a cutting-edge technology, great development potential and prospects.