關鍵詞：知識分享、信任關係、互惠行為、利他行為 ;Abstract Knowledge is an important factor that contributes significantly to the enterprise value, and creates competitive advantage for the enterprise. The foundation of knowledge improving lies in sharing. Aside from the factors from traditional social exchange theories, sharing intention is also affected by trust. Trust can be further categorized as trust in organizations, in supervisors and in colleagues. Previous studies even though have mentioned these constructs, failed to systematically probe into these three categories of trusts and knowledge sharing intention. This study strives to propose a model explaining the causal relationships between the three kinds of trusts and intrinsic and extrinsic benefits. It is concluded that reciprocity (extrinsic benefit) will affect trust relationship, and altruism (intrinsic benefit) is influenced by trust relationship. The findings suggest that reciprocal behavior is positively correlated with trust in the organization and the supervisor; trust in the supervisor has a positive effect on knowledge sharing; trust in the supervisor and trust in colleagues are positively correlated with altruism behavior; altruistic behavior has a positive effect on knowledge sharing. The study proves that extrinsic benefit has an effect on trusts on organizations and supervisors; while intrinsic benefit is affected by trusts on supervisors and colleagues. Based on the findings, managers are encouraged to provide emotional rewards besides financial rewards.