In order to improve the efficiency and quality of test, the reuse of test cases for weapon equipment software is discussed. The concepts of test items and test cases and the basic framework of the use case library are proposed. The Z specification language is used to describe the test cases in a unified way. The description method is used in the test case reuse examples of weapon equipment software, which can ensure the effectiveness of software testing and the universality, independence, standardization and easy modification of test cases. Through the reuse of test cases, the results show that the research can speed up the design progress of test cases, reduce the burden of testers, and improve the efficiency and quality of weapon equipment software testing.