冷活塞调控的PT/GM混合式新型制冷机是脉冲管(PT)和G-M制冷机的混合循环，它是综合现有小型制冷机优点的一种创新机种。本项目从建立这种制冷机热物理模型和实验研究入手，系统研究其内部流动和热力过程机制，研制出冷活塞调控的PT/GM混合式4K新型制冷机。

PT/GM hybrid refrigerator is a two-stage cryo-cooler which couples pulse tube refrigerator to G-M refrigerator. In the research of this project, the method have been adopted which combine the theoretical and experimental study. On the theoretical study, the thermal physic process of the PT/GM hybrid refrigerator has been clearly picturized by the numerical computation. On the experimental study, the prototype has been set-up, and a lot of experiments has been done on it also. The important result has been gotten: the effect of adjusting phase with the cold displacer is much worse than it with orifice and double-inlet, it is the best way to adjust phase with orifice plus double-inlet. The design method and rule have been drawn out too.