Abstract: In this paper, an algorithm of traffic shaping based on DLB is developed, which is used to smooth the traffic with a large fluctuation of output rate. This algorithm can estimate and compute the average input rate of traffic on-line by monitoring the variety of data buffer’s length. It updates the settings of traffic shaper depending on the rate change of source traffic so as to provide smoothed stream under the limited resources. The general problems of traffic shaping are given. And then the general principle of traffic shaping and a typical shape algorithm are described. The main ideas and working process of the proposed algorithm are introduced. An experiment which is used to verify this algorithm is given. Finally, the results of this experiment are analyzed and a conclusion is given.