This paper introduces the development of software testing technology, puts forward a method to obtain test cases from UML State Diagram. Test cases will be generated from the transitions (transition path) of the State Diagram. The method above is absolutely based on UML and can generate less but more effective test cases, which can be automated easily. Then we improve the depth-first-search algorithm and bring forward an algorithm to obtain test cases from UML State Diagrams, which travel the State Diagram ...