As the development of Internet, knowledge communities have become one of the main knowledge resources. However, the behavior of member participating is important for a knowledge community because it will result in the abundant knowledge and community growth. In this research, we will discuss the factors affecting member participating of knowledge communities with the view of exchange behavior. In addition to the tangible benefits and intangible benefits which are proposed in Social Exchange Theory (SET), this research also take the cognitive feeling into consideration in this revised exchange model. Moreover, the user satisfaction will be argued the mediating effect of member participating in such a revised exchange model. With the analysis of 336 questionnaires, the result shows that exchange of the tangible benefits, intangible benefits and cognitive feeling have impact on the member participating behavior in a knowledge community. And user satisfaction also plays the mediating role in the relationship of exchange behaviors and member participating in knowledge communities.