Nowadays, as the amount of video and population in VoD system keeping fast growth, service provider often use p2p mechanism to alleviate their server load. The user under p2p mechanism is not only resource consumer but also resource provider. Therefore, system performance is mainly determined by user watching and sharing behavior. In this paper, after analyzing a large amount of data, we present some valuable results on user behavior. Those studies are believed can possess guiding significance for analyzing system performance and design new pre-fetch strategy.