Aiming at evaluation and selection of maintainability design schemes, a new preferred selection method based on integrative evaluation of design factors was proposed. Considering the uncertainty and fuzziness of design factors’ evaluation, linguistic assessment values of maintainability design factors were quantified on the basis of the set pair analysis theory, and evaluation and decision-making model was established by introducing the weighting method based on AHP into similarity scale of schemes. Finally, preferred selection for design schemes of some manned spacecraft power system was taken as an example to illustrate the application and effectiveness of this method. 