中文摘要：

政府与社会资本合作模式（PPP）已成为推进中国新型城市化,加强城市基础设施建设的重要制度安排。PPP模式的实际运行涉及复杂的契约关系,其中政府和民营企业间的契约关系最为关键,由于双方在PPP模式中的目标导向差异和可能采取的机会主义行为,凸显出严重的契约治理问题。本文运用轮流出价合作博弈模型,论证了股权契约治理是政府和民营企业契约治理的核心内容。为鼓励民营企业积极参与城市基础设施PPP项目,政府应给予其较大的股权比例,同时需要形成政府和民营企业股权契约相互制衡机制,以提高城市基础设施PPP项目契约治理效率。

英文摘要：

Public-prlvate partnerships （PPP）has become the important system arrangement to promote new urbanization and strengthen urban infrastructure construction. The actual operation of the PPP mode relates to the complex contractual relationship, but the contract relationship between the government and the private enterprises is the key, for both sides have different goal orientation and possible opportunistic behaviors, which highlights serious governance issues. By the alternating offer game model of the cooperation, this paper demonstrates that the equity contract governance is the core of contract governance between government and private enterprises. In order to encourage private enterprises to participate actively in the PPP projects in urban infrastructure, the government should give the larger equity ratio. Meanwhile, it is necessary to form a mutual checks and balances mechanism of equity contract between government and private enterprises to improve contractual governance efficiency in urban infrastructure PPP projects.