Providing high rate streaming service over cellular data networks is a challenging work. In this paper, a mobile streaming broadcast system, called P2P-leveraged mobile live streaming system (P2PMLS), is proposed. In P2PMLS, the multiple network interfaces of mobile hosts are used. The mobile hosts form a peer-to-peer overlay networks through WiFi or Bluetooth. A part of the peers, called seed peers, receive streaming data from the server through cellular data networks and share the obtained data with other mobile hosts in the overlay network. The peer layer protocol is also proposed to manage the overlay network. Based on the design, a simple prototype is implementing. The performance of the design is compared with the cellular network streaming scheme in an analysis way. The results show that P2PMLS is superior to the cellular network streaming scheme.