Cross-layer design has been used in streaming video over the wireless channels to optimize the overall system performance. In this paper we extend our previous work (i.e. joint design of source rate control and congestion control for video streaming over the Internet) in [1] and propose a cross-layer design approach for wireless video streaming. By jointly designing the source rate control at the application layer and congestion control at the transport layer, and taking advantage of MAC layer information, our approach can avoid the throughput degradation caused by transmission error of the wireless channel, and better support the QoS requirements of the application. Simulation results show that the proposed mechanism can significantly improve the playback quality of the application, while maintaining good performance of the transport protocol.