This paper takes use of chaos related theories to analyze the real network traffic about its chaotic properties and prediction attributes. Owning to the good performance of chaos-based prediction in short term forecasting, the prediction-based DiffServ framework and the Dynamic QoS scheme are firstly given in the paper. The OPNET-based simulating result shows that the QoS performaces and the network’s throughputs in heavy-load environment are all improved remarkably, comparing with the traditional static QoS configuring and measure-based dynamic QoS setting methods.