The present thesis puts forward a hierarchical P2P model: self-adaptive P2P model of two-level. Super peers compose a self-adaptive DHT network on the top layer, and lower ordinary peers take super peer in the same group as their center server to form a cluster. Data are stored in ordinary peers and super peers hold indices of data and answer for request from ordinary peers. When super peer join or leave, it does not maintain consistency of entire network’s logic topology but only update routing table of its predecessor and successor, besides, super peers update their routing table cache when they transmit messages. The ordinary peers keep backup of super peer for system restore when super peer fails. System can optimize network structure by select peers with high capacity to be super peer and restrict amount of peers in each group.