In this paper,the structure and kinetic theory of linear compressors for small cryogenic refrigeration machines are introduced,and the research progress of linear compressors in major research units at home and abroad is summarized in the light of the literature and reports in the past 20 years.The key factors affecting linear compressors,such as magnetic circuit design,support technology and clearance sealing technology of linear compressors are concluded.Finally,the current future research trends of linear compressors for infrared detectors are proposed.