Abstract: To provide a basis for regional economics decision-making, based on the theory of fuzzy neural networks (FNN) an environmental Kuznets curve (EKC) was investigated quantitatively by predicting the coordination degree of environment and economic development. As an example, the coordination degree of environment and economic development of Chengdu City, Sichuan Province, was predicted, and based on the predicted result, the relationship between the environment and economic development of Chengdu City was analyzed. The analysis shows that there is not a marked peak value on its environmental Kuznets curve,i.e.,the relationship between its environment and economic development tends towards coordination.