Abstract: with the development of space technology,each kind of rem-ote sensing instruments are widely used in spacecraft,i.e. infra red detector、X ray γ ray and submillimeter wave detector etc must be operated in cryogenics,so as to improve sensibility and decrease thermal noise.So the refrigeration system is tlie essential and important component of space technology. At present the using refrigeration system are:passive refrigeration include storage system of refrigeration of radiation and cryogenic cold-producing medium;and mechanical refrigerator.This article mainly indroduces the classification and feature of space refrigerator,the refrigerators that we have used or will use in the future.