Abstract: Measuring interactive performance is the important basis to analyze and improve desktop computing system. The difficulty of measuring interactive performance is how to get exact measurement result conveniently. Exact measurement requires establishing the corresponding relationship between output events and input events. The necessary restrictions for finding the output events of input events are analyzed in this paper. Then we propose an interactive performance measurement method using restricted behavior policy. The method consists of session recorder assistant and user behavior validator. Session recorder assistant is used to record user events and transform unqualified events simultaneously, and user behavior validator is used to check whether all recorded events are valid. Through these two steps, all events are ascertained to get exact measurement results. We implement an interactive performance measurement tool named VNC-IPA using the method. We conduct experiment to compare the accuracy of VNC-IPA and VNCplay. The experiments treat slow-motions result as true value, and it shows that the average of relative errors measuring with VNC-IPA is decreased by 35.4% with respect to VNCplay. Experiments results show that our method can get exact measurement results for interactive events conveniently. Besides, our tool is independent of operating system and can be used in Windows and Linux.