高速公路建设资本金不足，特别是地方自筹资金的缺失，是影响公路建设债务风险的重要因素之一。通过政策分析与行业实践相结合的研究方法，分析了混合所有制经济对公路交通建设投融资的指导意义，研究了PPP模式的特点及其应用条件。研究结果表明：在PPP框架下建立高速公路股权投资基金，代表社会投资者以优先股的方式投资49%的高速公路股权，既保证投资人有合理稳定的回报，又解决了高速公路项目资本金的实际到位问题，促进公路交通行业逐步建立可持续发展的长效机制。同时，交通主管部门以持有普通股的方式进行管理，并不丧失对公路的管理权，可以保证高速公路公益性的一面，以及政府对公路收费政策的管控权，从而形成以PPP模式为基础的高速公路混合所有制经济新常态。

The lack of the expressway construction capital, especially the local self-financing, is one of the important factors of road construction debt risk. By policy analyzing and practicing , the guiding significance of mixed ownership economy to the investment and financing of road traffic construction was analyzed. The characteristics and application conditions of PPP mode were also studied. The results show that: equity investment fund established under the expressway PPP framework, representative of social investors, to invest in preferred shares 49% stake in the highway, not only can ensure people have a reasonably stable investment returns, but also can solve the problem of the actual place of expressway capital projects, which will promote road transport industry to gradually establish long-term mechanism for sustainable development. Meanwhile, the transportation departments approach to management in the manner of holders of ordinary shares does not lose the right to manage the highway. This way can ensure welfare side of the expressway, as well as the control right of the government to the road toll policy, and thus a new norm of highway mixed ownership economy based on the PPP mode can be formed.