Abstract: Regression testing based on agile development mode is faced with the problem of fast delivery. So a new algorithm is proposed. Firstly, the regression test cases are divided into new function test cases and original function test cases, and different algorithms are adopted: analyzing the mapping relationship between requirements and modules as well as between modules and test cases, completing the sorting of new function test cases; combined with the original sorting, and analyzing the impact of new functions on the original functions, as well as the execution of test cases, completing the sorting of original function test cases. Then the priority of test cases is adjusted dynamically during the execution. Finally, through the experiments on the open data set of Google, the effectiveness of the algorithm is verified. The average APFD value is 98.08%.