Abstract:    Under the background of green development and digital transformation, this paper explored the relationship between heterogeneous environmental regulation and SMEs′ green innovation and the linkage effect of digital investment, which helped SMEs to build a synergistic mechanism between technological innovation and green development and enabled them to enter into the benign track of high-quality development. Taking SME and GEM board listed companies as samples from 2012 to 2020, we constructed a two-way fixed-effect model to test the relationship between heterogeneous environmental regulation and SMEs′ green innovation and the linkage effect of digital investment. The empirical results showed that: (1) there is a significant U-shaped relationship between command-control, public-participation environmental regulations and SMEs′ green innovation; however, there is a significant inverted U-shaped relationship between market-incentive environmental regulations and SMEs′ green innovation; (2) digital investment not only has a significant promoting effect on SMEs′ green innovation, but also positively moderates the U-shaped relationship between command-control, public-participation environmental regulation and SMEs′ green innovation, and negatively moderates the inverted U-shaped relationship between market-incentive environmental regulation and SMEs′ green innovation; and (3) there are significant regional differences in the relationship among heterogeneous environmental regulation, digital investment and SMEs′ green innovation. The above conclusions will provide useful references for the government to flexibly take environmental regulatory tools, optimize and adjust the environmental regulatory mechanism to promote SMEs′ digital transformation and green development.

Key words:  heterogeneous environmental regulation, digital investment, SMEs′ green innovation