中文摘要：

通过审视新古典经济学完全竞争和完全可竞争市场理想化模型可知，在市场完全条件下，没有沉淀成本和交易成本，至少可以实现帕累托次优。一旦引入规模经济（自然垄断）、沉淀成本和交易成本概念．并且这些经济变量相互作用，市场很容易失灵．不仅为私人缔约奠定了理论基础，而且还为政府管制提供了正当理由。尤其当政府管制本身遭受交易成本困扰时，就会出现“管制刃锋”问题，所以需要理性地权衡市场竞争、政府对私营企业管制和国有企业“三位一体”格局．正确处理竞争与垄断市场结构、私有与国有治理结构．以及确立政府管制结构的基本原则．对于深化我国自然垄断行业改革具有重大的理论与现实意义。

英文摘要：

This paper is to analyze the perfect competition and contestability market benchmark model, we found that without scale economies, sunk or transaction cost, Pareto optimality may be realized. Hence we introduct scale economies, sunk and transaction costs to take into account market and governace structure, at the same time market and governance failures result from natural monopoly market, and we discuss that private ordering and government regulation play an important role in economic development. Particularly the regulation is concerned with transaction cost, and regulation edge occurs. Under these conditions we need the regulation model tradeoff of the market competition, private ordering and regulation structure and its implications for China＇s natural monopoly reform, and manage sunk and transaction costs under scale economies.