In the actual life cycle of software, due to various reasons, the time that spending on software testing is often not enough to perform the comprehensive test. Coverage ratio and the number of test cases as the main quality factors, have been payed more attention to. However, the execution order of test case as one of the important factors that affect test efficiency, has not caused enough attention. This paper presents a test case generation technology based on genetic algorithm, which considering Coverage ratio, the number of test cases and the execution order. Testing personnel can execute test case in the established order and accomplish the most important software function test in the time as shorter as possible according to the method referred in this paper.