More and more employment websites have provide recruitment services. Some of them are commercial websites, others are government-sponsored websites. The biggest problem for these centers is that there is no information sharing among these sites. This paper would assume each website as a knowledge or information node and analyze the possibility of knowledge sharing and the sharing architecture from the viewpoint of information sharing, then set up a virtual knowledge service market with rewards and punishments mechanism. Finally, through empirical experiment, the knowledge trading mechanism with rewards and punishments could significantly improve the knowledge efficiency.