The test case generation from design specifications is an important work in testing phase. In this project, we use UML activity diagrams, class diagrams, sequence diagrams and use case diagrams as design specifications, and present an automatic test case generation approach. The approach first randomly generates diagram in design phase in software development process. Then, by exporting data into prescribed data format, into a specific storage data implementation work will further process the input data. The developing will take input as exported data. The approach can also be used to check the consistency between the program execution traces and the behavior of UML activity diagrams. Test driven design (TDD) and design driven testing (DDT) are used for test case generation. TDD generates so many duplicated test cases at the end of the project. DDT is novel approach to generate test cases based on design model of application. Test optimal is a tool to generate test cases based on model driven environment using UML activity diagrams. Traditional approach generates many numbers of large and duplicate test cases. Proposed approach will minimize generated test cases and generate optimal test suite using model driven natural language based knowledge. Filtering will lead to better available resource utilization and will improve software project management.