The nature of self-organized P2P network is that most nodes are autonomous and rational which leads to the conflict between the top objective of the system and own interest of the node. An cooperation incentive mechanism can introduce altruistic behaviors, decrease the conflict between the system and the individual. In order to improve network availability, the author discusses a few efficient, practical distributed cooperation mechanisms and points out the pending problems and research directions in the design of cooperation mechanisms in self-organized P2P networks.