Abstract:Using the panel data of China’s 30 provinces during 2000 to 2014 and the threshold regression method with industrial agglomeration treated as a threshold variable, this paper empirically analyzes the effects of industrial agglomeration, the coupling effect between industrial agglomeration and urbanization on pollution emissions, and then separates the sampling population into four groups, i.e., eastern, central, western and northeast China to examine whether there exists regional disparity on environmental externality of industrial agglomeration. The results show that: (1) The relationship between agglomeration and pollution is inverted U shaped; (2) agglomeration can reduce pollution emissions through the promotion of economic development; (3) the benign interactions between agglomeration and urbanization significantly cut down environmental pollutions; (4) urbanization plays an important role in determining the threshold value of pollution effect of agglomeration, verified by the fact that eastern China has the highest urbanization level and the lowest threshold value among four groups.