Abstract: The psychological contract has decisive effects on staff's attitudes,behaviors and performances.At knowledge-based economy ages,the knowledge-based staff has already become the main soldier of the business enterprise,its important function become more and more obvious.But because of the knowledge-based staff possess singly characteristics and business enterprise exist some problems in managing knowledge-based staff,make the knowledge-based staff widespread lack a loyalty,but the practice certificate development knowledge-based staff's loyalty is the valid path that raises the performance of knowledge-based staff's,so this paper combines the knowledge-based staff's characteristics and psychological contract put forward strength of loyalty of the knowledge-based staff.