With the expanding range of computer applications, computer applications is used more and more in key areas, so it requires higher quality and reliability for software. As the most important techniques for software quality and reliability, software testing becomes more and more important in software development. Though software engineering technology development continuously put forward new requirements for software test technique, software test model and test case generation have always been the core of the software testing, and it is important to choose the better test models and test methods to improve the efficiency of test cases. Considering that most of software errors can be attributed to the difference between design and implementation, this paper presents a software testing method based on the design model by analyzing the design model and the implement model extracted from design process and converting to formal test models, and finally compare the design model and the implement model to find out the difference between requirement and implement.