Due to the fact of high amounts of nonperforming loans in Japan and China,this dissertation studies behaviors of state-owned commercial bank managers(agents)in their(constituent or principal)branches.The first section is introduction which emphasizes the inevitability of this research and reviews all the relating mate-rials and references.The second section studies their behaviors under pay off matrix by expanding the monitor model.The third section draws conclusion as the nonperforming loans are created because the commercial banks employ game theory to realize the maximum effectiveness with their own behavior index based on different be-havior index systems.That is to say,the behaviors of state-owned commercial bank managers are not completely supervised or checked-up under the monitor model.