Abstract: Materials play an important role in the spacecraft thermal control subsystem. This paper discusses the demand of thermal control materials and their applications in the system. The focus is on the effects of space environment on thermal control materials. It is shown that some key materials should be developed, such as high performance heat-conducting materials and heat-protection materials, intelligent thermal control coatings and new functional thermal control materials, in order to meet the demand in the development of the spacecraft system and thermal control technologies.