Abstract: The tribological design of space machinery is discussed in this paper. It is indicated that in order to ensure the operation reliability of space machinery the lubrication mode and materials should be selected reasonably according to tribological knowledge, while determing the structure, strength and dynamic design for space rubbing couple. The author considered that systematically accumulating the basic knowledge of space tribology and characteristics data of lubricating materials, as well as establishing the mathematical relationship between the basic properties and practice of the materials are the prerequisite for tribological design of space machinery. In addition, the methods and steps of tribological design were suggested as follows: selecting lubrication mode and materials based on the environmental and operating conditions, and determining the structure, strength and kinetics design of the rubbing couples according to the properties of lubricating materials.