As non-cooperation behaviors such as free-riding do not seems to have been checked according to a recent survey of Gnutella network [3], it hereby calls for more attention to this issue and more efforts in our future research to protect P2P networks. This paper presents a new incentive architecture- "Pyramid", whose idea first came out as a sales mode named "Pyramid Selling". By introducing this concept into P2P research, we believe the "magic" of encouraging sales in reality could also benefit the P2P world on encouraging cooperation. In particular, the paper describes in details the three layers of Pyramid?s hierarchical structure: fundamental infrastructure managing the peer organization and basic utilities, trade-based credit system supporting trust management and service charge and pyramid incentive mechanism encouraging cooperation of rational users. Model evaluation and discussion of the proposed pyramid incentive mechanism demonstrate its effectiveness in encouraging cooperation and discouraging non-cooperation respectively.