对城市轨道交通公私合营项目社会投资人的投资回报模型进行分析，并对项目公益性和经营性的双重属性进行深入研究，提出一种基于投资额、运营成本、票款收入、补贴金额等数据对项目的经营性进行量化测算的方法，得出项目经营性量化测算的基本原则——使超过传统模式的融资成本部分等于运营期各项支出的节约部分，并以北京地铁4号线为例进行实证研究。

Through analysis of social investors’return on investment under public-private-partnership ( PPP) model and in-depth study on the rail transit industry’s profitable and non-profitable properties，a quantified estimation method based on investment， operating costs，income and financial subsidy is proposed，and it is concluded that the basic principle of the quantified estimation method is to make the excess cost of financing equal to the cost savings in the operation period． An empirical research on Beijing metro Line 4 is presented in the end．

F530． 7