Under the hypothesis of rational economic man,trilateral game model of supervisor,small and medium-sized shareholders and controlling shareholder to find out Nash equilibrium and to combine policy meanings of each parameter with variable is constructed.In the aspects of market supervision with company management,the regulations related to civil compensation responsibility in securities law and related laws should be reinforced,supervisors should strictly enforce the laws,increase cost of controlling shareholders' encroaching on benefit,use advanced method to decrease supervising cost and promote judging ability and right-protection consciousness of small and mediumsized shareholders,reduce share rate of controlling shareholder and increase benefit of the company.