The scale of test suites is constantly expanding and the cost of testing is increasing due to the change of test requirements in the process of regression testing. In order to solve the problems, a Reduction method of Test suites based on the analysis of Mutation (RTM) was proposed. Firstly, the test suites were classified and the transaction set matrix of mutants was created in binary numerical form according to whether the designated mutants could be detected or not by test suites. Then, the correlation relation between test suites was obtained by using the improved association mining algorithm. Finally, the test suites were effectively reduced according to these relations. The simulation experimental results of the six classical programs show that, the test suite reduction rate of the proposed RTM can reach 37%. Compared with the traditional greedy algorithm and heuristic algorithm, the proposed RTM improves the test suite reduction rate by 6%, and can guarantee the test coverage rate at the same time, even the test coverage rate of a single test suite increases by 11% on average. The proposed method can meet more test requirements by using fewer test suites, effectively improving test efficiency and reducing test cost.