Abstract: In the process of the franchise project construction, there are two different forms of cooperation between the government and the private:the full cooperation and the non-full cooperation. Under the full cooperation, the government and the private sector are integrated into a whole body to jointly build projects, and the government shares profits and risks with the private sector. Under the non-full cooperation, the private undertakes the job of investment, financing, construction and management of the project, while the government only has the right to supervise the project, and they do not have its management right. This leads to the differences on the decision objects of the two forms of cooperation. Under the full cooperation, the government and the private have the same goal, namely maximizing the total social welfare of the toll road throughout its life cycle. Hence, a single objective concession period decision model is established. However, under the non-full cooperation, the government only focuses on the social welfare of the project during the transfer period, while the private only focuses on the economic benefits during the franchising period. Based on these, a bi-objective concession period decision making model is built to maximize the private's and the government's benefits. In this paper, there may be some conflicts of interest between the two sides, so the negotiation power is introduced to assess the ability of one side against the other side eroding its benefits. Then, the influence of the private's negotiation power on concession period decision is analyzed. The conclusions are:under the full cooperation, the negotiation power has no influence on the concession period decision, and the concession period is the entire project life; under the non-full cooperation, the private's negotiation power has a positive impact on the length of concession road and the total social welfare which is created by the toll road. Furthermore, when the private's negotiation power is weak, it can prove the bargaining position by raising the profit level of the unit operation cost to extend the concession period, and to gain more benefits.

Key words: franchise project, negotiation power, concession period, non-full cooperation