Abstract: To tackle the problems of consistency, completeness and automation in the area of functional testing of embedded controllers, an approach of generation and construction of test-cases based on timed automata is presented. Firstly, a formal notation is proposed to model the structural and behavioral aspects of a function, and then a method is presented to generate test-cases from the behavioral model. Furthermore, in order to reduce the number of test-cases, a number of rules was used to select and construct typical test-cases, and prove the completeness of the generated test-cases. Finally, a case study illustrates the implementation of the testing system and its actual effects.