Abstract: Based on the theory of nonlinear econometrics, this paper takes the environmental regulation intensity and the degree of element agglomeration as threshold variables to establish panel threshold regression model, in order to exploring the impact strength of environmental regulation and element agglomeration on TFP and its decomposition. The results show that the environmental regulation presents dual, triple and single threshold effects to environmental TFP and its decomposition, while element agglomeration presents triple, dual and dual threshold effects to them. The effects of the provincial environmental regulation intensity and the degree of element agglomeration show an apparent polarized phenomenon. The government should moderately control the environmental regulation intensity and make it transfer to the medium group, so as to achieve the positive externalities of environmental TFP. Moreover, each province and city should continuously stride over the threshold level of element agglomeration degree, which is the key to achieving the scale economy of environmental TFP growth as well as promoting the collaborative development of economy and environment.

Key words: environmental regulation; elements agglomeration; TFP; threshold effect