The invention provides a cost optimization-based P2P streaming media coverage network topology structure adjustment method. In the method, the dynamism and isomerism of nodes are fully considered, the topology information of nodes, link delay between the nodes and available uplink bandwidth of the nodes are utilized, high-capacity nodes are greedily selected from alternative nodes to serve as service nodes by calculating the weight of the link between the nodes and the capacity value of the alternative nodes. Meanwhile, due to an adaptive topology adjustment method for periodically and continuously adjusting nodes with high bandwidth and long survival time to be close to a video source, the nodes in the network can gradually learn the network status and continuously optimize the system performance. A coverage network topology constructed by the method can improve the data diffusion speed, ensures the stability and continuity of streaming distribution, and effectively reduces the flow cross operators.