To address the problem of high rate of dropping packets in high network flow of Snort network intrusion detection system, a way of multimedia data identification in network flow and two approaches to processing multimedia data has been designed by analyzing the characteristic of multimedia data in this article. The method of Dynamic Self-Adapting Multimedia Data Processing is also introduced. According to the changes of network flow and the capability of Snort disposal, this method could automatically adjust the way of detecting multimedia data. This method could effectively reduce packet loss ratio of Snort.