Abstract: The compressed video presents the striking VBR characteristic. The rate smoothing should be considered during the streaming transmission of this video. The video maybe goes through some subnets that have different network characteristic from the video server to client, and new challenges add to the smooth methods. Discussed in this paper is the problem about the streaming and smoothing transmission of the stored video along heterogeneity network path. Based on the buffer provided by the node between heterogeneity networks, a smooth model and a smooth algorithm are proposed, and it is proved that the result of the algorithm is optimal. Finally an application example is given and the efficiency of the results is evaluated.