Reuse of software data from different sources to civil aircraft airborne software and the different reuse methods may have impact on the full compliance of airborne software.To achieve cost and risk reduction in software reuse project, the classification of civil aircraft airborne software reuse is made and the software reuse assessment elements are given at first.Then, the software reuse assessment framework and process are established, and the assessment activities and sequences are specified.Finally, the airborne software reuse requirements are given from the perspective of actual certification, and one example of software reuse assessment and certification is presented.The study provides a support for the recognition and assessment of software reuse, and for making certification strategy of software reuse in the early stage of project.