Abstract: An application validation method for space components, as an enhanced reliability insurance approach, is proposed to verify the maturity and the adaptability of the components. It is based on the conventional qualification test of components, while taking account of the component's application background and its characteristics, to form an assessment scheme to evaluate the component's tolerance margin and actual performance. This method is implemented to ewduate the space-level 1553B data bus isolation transformer. The variations of its electrical parameters in different application conditions are obtained, with a comparison between the domestic·made and the imported similar products. Verification is also made whether its structure satisfies the aerospace requirements and the requirements for its limit performance. It is shown that this method is practical and carl provide a comprehensive reference basis for the development of space components.