Abstract: The electrical insulation performance of space electronic products constrains the boundary of the transmission and action of the spacecraft's electrical signals. The relevant test verification should be carried out in the development process of the spacecraft. This paper focuses on the key problems to be considered in the electrical insulation test selection, the design and the implementation in the component level. The space environments and the effects are analyzed first. The principle for selecting the electrical insulation test items and the method for tailoring the test parameters are discussed. Different electrical insulation test systems are classified. And the key problems of the discharging test are highlighted, to provide a reference for designers and process engineers to plan and implement electrical insulation testing.