Improving the green utilization efficiency of industrial land is an important way to achieve sustainable land use and development of industrial economy with high-quality， and the agglomeration of manufacturing （AGG） industry is an important factor affecting the green utilization efficiency of industrial land （EIL）. The panel data from 30 provinces in China from 2000 to 2019 were used to study the mechanism and effects of manufacturing agglomeration （AGG） on the green utilization efficiency of industrial land （EIL） from the perspective of environmental regulation （ER）. The results showed that the green utilization efficiency of industrial land （EIL） in China from 2000 to 2019 had a trend of steady increase followed by rapid growth， with an average annual growth rate of 2.942%. The green utilization efficiency of industrial land （EIL） in the eastern region of China remained higher than that in the central and western regions of China， with an average annual growth rate of 4.993% and 1.061%， respectively. The effects of manufacturing agglomeration （AGG） on the green utilization efficiency of industrial land （EIL） had a threshold characteristic with the changes in the intensity of environmental regulation （ER）. There was a U-shaped relationship between the manufacturing agglomeration （AGG） and the green utilization efficiency of industrial land （EIL） with the increase of the intensity of environmental regulation （ER）. It was found from heterogeneity analyses that the negative effect of AGG on EIL gradually weakened with the improvement in the level of ER from 2000 to 2009， and had a negative to positive trend from 2010 to 2019. Voluntary ER was the first to generate a threshold effect， while market-oriented and command-and-control types of ER were observed to manifest at a higher level of ER. It is indicated that the differentiated policies for environmental regulation （ER） should be formulated to upgrade the industrial structure of manufacturing industry and the green utilization of industrial land.