Though we can find the separate research of the antecedents of member commitment, there has been little systematic research into member commitment within agricultural cooperatives, especially the way how these antecedents (or correlates) affect member commitment. Using a sample of 391 farmer cooperative members in China, this study investigates whether trust and social pressure affect cooperative member commitment and if so, whether the effect is mediated by member participating in the decision-making process. Our study finds that trust is positively associated with three components of member commitment – affective commitment, continuance commitment and normative commitment, while social pressure is positively related to normative commitment. Participation plays a partially mediating role between trust and social pressure and member commitment. Generally, these findings offer empirical evidence on the important role of cooperative chairman between members and Chinese cooperatives and on the influence of social pressure with Chinese characteristics in maintaining cooperative membership.