Video streaming transmission process shows a low bandwidth usage efficiency in the P2P IPTV applications, an adaptive video streaming transmission algorithm of P2P IPTV is proposed to resolve this problem. Firstly, the target problem is formulated as a multi-segment streaming PSNR maximization problem, the target problem is solved directly through a dynamic programming algorithm; then, the optimal class subscription and class transmission strategy are selected to maximize the total video quality of the important region in the video segment; lastly, a new request model is designed to handle the unrecoverable data transmission, if it exists the unrecoverable media data in the important region of the receive node, it will periodically broadcast its buffer map as a request signal to all neighboring nodes, so that the unrecoverable data transmissions will be filtered. Experimental results based on the standard H.264/SVC video sequence show that the proposed algorithm could improve the bandwidth usage rate of P2P network streaming, and the received videos of the clients will realize a high quality.