Integrating Peer-to-Peer streaming with wireless networks is a promising technique which promotes ubiquitous multimedia services. Rate allocation within this context is essential to the overall performance of a streaming system due to the limitation of wireless network resource. Optimizing rate allocation in wireless P2P streaming poses us the twofold challenge: the data flow rates are not only constrained by P2P overlay uplink capacity, but subject to the resource sharing mechanism of wireless networks. In this paper, we propose a utility-based rate allocation framework to optimize the flow rates in wireless P2P streaming systems. Our optimization framework involves both P2P overlay constraint and wireless channel sharing constraint. We propose a channel-aware approach to address the modeling of wireless channel sharing patterns. We then proceed to design a distributed double pricing algorithm to solve the optimization problem. Experimental results validate that our algorithm can achieve convergence of data flow rate allocation and optimality of network throughput.