Abstract: The recently emerging P2P technologies have huge potential on resource usage and system scalability. Providing P2P-based media streaming service, which is an important application over the Internet, has attracted a lot of research interests. In P2P media streaming with the pattern of multiple senders and single receiver, it is still a challenge to optimally allocate streaming rate and media data among multiple senders. To cope with the problem, a new solution is proposed. Firstly, the authors model the optimal rate allocation problem as a non-linear optimization problem by applying queueing theory, and derive the optimal rate allocation formula that computes the optimal solution. Then, a new optimal rate allocation algorithm(ORAA) based on the formula is proposed. The ORAA algorithm can produce the optimal solution and the optimality of its solution is proved. Finally, based on the ORAA algorithm, a dynamic rate allocation algorithm (DRAA) is proposed, which can dynamically adapt to network fluctuation and optimally allocate streaming rate and media data among multiple senders. Because of its short running time, the DRAA algorithm can be used in real time. Extensive simulation results using NS2 show that the proposed DRAA algorithm effectively reduces calculation and communication overheads, and achieves a better performance than the related works with different parameters.