Abstract: All interest subjects interact each other in the government-led ecological construction projects, and theirs strategies interdepend on each other too. It is feasible that using the game theory to study the interaction relation between different interest subjects in ecological construction projects. Turning Cultivated Land Back Into Forests and Grasslands Project, which is a typical ecological construction project, is taken as a study case to establish game model. Then the model is researched from two aspects of static and dynamic, respectively. The results show that the central government should arrange more project tasks at the regions of lower development level and fragile ecological environment. Meanwhile, for ensuring the smooth implementation of the project, the proportion of subsidy given by the central government to this region should be raised; If there are no the mechanism of supervision and assessment made by the central government, and the project amount which farmers and herdsmen finished have no effect on the external effect of local government, the local government may ignore the benefit of farmers and herdsmen. As project specific performer, farmers and herdsmen mainly focus on the proportion of subsidy given by government and the project amount, then make decision to finish specific percentage of the tasks amount, but pay little attention to the problem of government's "credibility". Therefore, the project decision-maker should consider the region differences and implement different policy items in the process of implementation of the project. Furthermore, the central government should play a leading role in the project.

Key words: ecological construction, game model, Nash equilibrium, government, farmers and herdsmen