In the past few years, there have been tremendous interest in the peer-to-peer(P2P) content delivery. This communication paradigm dramatically increases the traffic over inter-ISP links. In particular, BitTorrent(BT), the most popular P2P application, generates a huge amount of traffic on the Internet. BitTorrent’s performance is limited by the fact that typical internet users have much lower upload bandwidths than download bandwidths. This results in the overall average download speed of a BitTorrent-like file download system to be bottle-necked by the much lower upload capacity. We think about to utilize idle users’ spare upload capacity to largely improve the download speed beyond what can be achieved in a conventional BitTorrent network. In this paper, we design a system that is completely compatible with the already existing clients who conform to the BitTorrent protocol, at the same time, we analyze this system’s steady-state performance and present simulation results.