Abstract:    China′s economy has shifted to the stage of high-quality development, and accelerating the improvement of green technological innovation quality plays a key role in achieving high-quality, green, and low-carbon economic development. Based on the panel data from 243 prefecture-level cities between 2004 and 2016, this study empirically examined the impact of the development zone upgrading policy on urban green technological innovation and its underlying mechanisms by using a difference-in-differences (DID) model. The results showed that the development zones upgrading policy significantly improves the quality of green technological innovation, and this effect remains robust after a series of checks, including the inclusion of pre-treatment variables and the exclusion of contemporaneous policy interference. In terms of the mechanism, the policy enhances the intensity of environmental regulation and increases government subsidies, thereby boosting the quality of urban green innovation. The heterogeneity analysis indicated that the positive impact of the policy on innovation quality is more pronounced in the cities with higher economic development levels, sufficient technological support, and stronger government resource control. The findings will provide important policy insights for further improving green location-oriented policies and deepening the green innovation-driven strategy.

Key words: development zone upgrading policy, green technology innovation quality, environmental regulation, government subsidy