Over the years,the model of China securities market supervision did not follow the economy in the transaction costs and resource allocation,but the path of the state system for country’s preferences,and the compulsory arrangements for transition path didn't consider the efficiency and cost factor. The paper deduces the equilibrium point of individual objects from revenue and cost analysis,based on this the paper also structures the appropriate supervision line of the whole market,and tries to find the best borders of supervision. Such a mode of supervision is in fact between the weak border and the strong border,and the implementation relies on enforcement of selfdiscipline and strengthening executing the law.