Abstract: Abstracts: This paper is based on the theoretical framework of “factor flow-industry interaction-space linkage” of cotton industry cooperative agglomeration. Taking China’s cotton origin from 2003 to 2022 as the research object, it empirically researches the impact of cotton industry cooperative agglomeration on cotton green total factor productivity and its functioning mechanism.The study found that: 1) The cotton industry synergistic agglomeration and cotton green total factor productivity show an “inverted U-shape” relationship that first promotes and then inhibits; 2) The synergistic agglomeration of the cotton industry has a “self-reinforcing” cumulative cyclical effect, and its effect can last for four years; 3) The inflection point is located at the 94.12% quantile of the sample, indicating that the vast majority of China's cotton producing regions are in the promotion stage at this stage; 4) The impact of synergistic agglomeration in the cotton industry on green total factor productivity in cotton is significantly heterogeneous in terms of natural resources and factor demand elasticities; 5) Cotton industry synergistic agglomeration acts on cotton green total factor productivity through three mechanisms: competition effect, knowledge spillover effect and scale effect. The competition effect and knowledge spillover effect can alleviate the “inverted U-shaped” relationship, while the scale effect strengthens the “inverted U-shaped” relationship. Knowledge spillovers and scale effects can push the inflection point to the right and widen the interval of the facilitation phase, while excessive competition can push the inflection point to the left and lead to an earlier inhibition phase. Finally, suggestions were made to optimize the layout of the cotton industry, avoid excessive competition, and develop moderate-scale operations to achieve high-quality development of the cotton industry and help modernize Chinese-style agriculture.