In order to achieve the integrality of the supportability analysis during the development phase of materiel, the determination method of corrective maintenance task items was presented based on the characteristics of failure mode, effects and criticality analysis(FMECA), the calculation of semantic similarity and the research of similarity for the units and systems. This method accounts for the bias of similarity calculation of units which is due to the unsurely level of unit-s failure mode, and according to the similarity of units to complete the quantitative similarity calculation of system to assist the determination of corrective maintenance task items which depends on the similarity of different materiel. In addition, because of using the computer-aid, this method not only improves the effect and efficiency for the calculation process, but also somewhat avoids the differences between different supportability analyzers because of their own experiences and diversity. This method regulates the process of determination of corrective maintenance task items. The final example proves the method is effective.