Space Heat Switches (SHSs) have wider and important applications in thermal control fields of deep space detectors, space coolers and some spacecrafts. This paper overviews heat transfer mechanisms of SHSs and their structures, key techniques and the advantages and disadvantages of every kind SHSs. Then it reports research progress of the SHSs in recent years, summarizes existing researching work and points out the developing directions of the SHSs. Finally, the authors suggest that those SHSs with high switch ratios and high reliability will be the research emphasis in future because they work at different conditions and require different thermal conductivities, also because the field of space exploration has been extended continuously. Moreover, some component manufacturing and material preparing technologies related to the SHSs will receive much attention, such as the development of new type of drivers, new thermal control coatings and their treatment processes as well as the precision machining and assembly technologies of components.