结合目前北京轨道交通上盖一体化、沿线地下空间一体化、站域综合体一体化开发、沿线土地一体化开发的典型案例，对其相关政策、体制、投资、开发模式等问题进行深入探讨，总结出一套“统一主体，统一规划，同步设计，同步实施”的开发模式，提出需要大力进行政策、体制、立法的创新，进一步助推北京轨道交通一体化事业的健康持续发展。

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

U239． 5