Event-flow model is a GUI testing model that describes the immediate execution relationship between GUI events, while GUI is based on event-driven mode. To improve the relationship between GUI events, information to describe the interactive relationship between GUI events is added in the event-flow model. The interactive relationship is based on sharing variables or exchanging messages. Then, an algorithm is given to generate effective and interactive GUI test cases based on interactive event-flow model, and the result of an experiments shows that this method obviously reduced the number of GUI test cases.