Environmental impact assessment (EIA) system has gradually developed in China while several problems still exist in the ecological environment protection implementation as the obstacles. This paper summarized the regular EIA process of China and picked up the stakeholders basis of case analyzing. A multi-stage and dynamic incomplete information game model was established to investigate the interactions among government, enterprises and EIA organizations and explain strategy selection of EIA participants according to perfect Bayesian equilibrium theory and scenario analysis. Furthermore, a suggestion was proposed to improve effectiveness of EIA system in China after discussing the present demerit. Results showed that in a short term, government and enterprises tended to choose evading EIA for their private benefits. But in a long run, they would be willing to take EIA because environmental deterioration would seriously affect their economic benefits. Thus they had to pursuit social benefits firstly instead. The public played a silent role as a victim in EIA system of China currently, caused by present beneficial balance of government, enterprises and EIA organizations. Some countermeasures must be brought out to develop the public participation regulation in the management system in order to break that balance and improve the effectiveness of EIA.