Abstract: Peer-to-Peer (P2P) worms have become one of some major threats to peer-to-peer network security nowadays. With its strong hidden feature and destructivity, the P2P worms can attack the goal nodes accurately by manipulating the router table of infected nodes, getting information of their neighbors and constructing a target list. Through some simulation experiments, this paper analyzes the characteristic of P2P worms spreading through BitTorrent network, and tests the effect of some parameters. The performances of simulation experiments show that the spread of P2P worms is related to the state of BT network, the attack capacity of worms, the rate of initial infected node, and immune node per unit time.