Abstract: Based on a Theory of Reasoned Action(TRA), a TRA model is constructed to examine the driving variables which systemically motivate employees’ knowledge sharing behavior. A structure equation model was used to analyze the data from 125 questionnaires and the results proved that: (1)the TRA model was a suitable structure to explain knowledge sharing behavior; (2)positive attitudes and subjective norms for knowledge sharing significantly impact the individual’s knowledge sharing behavior; (3)the impact of subjective norms was partly mediated by attitudes; (4)rewards, relationships, and expectant benefits significantly impacted the attitudes toward knowledge sharing; and (5)achievement and reciprocal responsibility significantly impacted the subjective norms for knowledging sharing. All these results provided a system perspective to improving the knowledge management policy in the organizations.