High-quality economic development resides in technological innovation and industrial carbon productivity. Based on the panel data of 288 prefecture-level cities in China from 2011~2021, this paper measured the level of green technology innovation by the number of granted green invention and utility model patents. It then applied an unexpected output super-efficiency SBM model to calculate urban industrial carbon productivity. The system Generalized Method of Moments and the spatial Durbin model were adopted to explore the impact of green technology innovation on urban industrial carbon productivity and spatial spillover effects. Research indicated that: ①There was a significant spatial correlation between the level of green technology innovation and industrial carbon productivity among cities in China, with high to high class cities concentrated and expanding in scope. ② Green technology innovation boosted urban industrial carbon productivity, to a great extent. Such effect was particularly pronounced in western regions, resource-based cities, and lower-income cities. In these cities, green technology innovation helped enhance productivity more effectively. ③ Under different spatial matrices, the direct effects of green technology innovation on urban industrial carbon productivity were significant, which suggested that such innovation clearly improves local urban industrial carbon productivity. What should be noticed is that, the indirect effect of knowledge spillover phenomenon such as green technology innovation dissemination that relies on face-to-face interaction was only significant under the inverse distance square matrix and economic distance nesting matrix. To some extent, these spillovers were weakened by a siphon effect, which inhibited the productivity gains of surrounding cities. Among the factors considered, geographical and economic distance nesting exerted the strongest influence on how green technology innovation affects industrial carbon productivity. Building upon these insights, the country should break away from the governance mode of "self-reliance" in cities, and build an intercity green collaborative governance system. These measures help ensure that R&D investment is channeled to the most efficient locations, breaking through geographical boundaries to form a regional industrial carbon reduction synergy.