Renewable energy technology innovation (RETI) and green industrial structure upgrading (GISU) are crucial pathways for China’s pursuit of sustainable development. Despite the existing research separately emphasizing the importance of RETI and GISU, there are limited investigations into the role of RETI in facilitating the process of GISU, especially in terms of empirical evidence at the urban level. This study utilizes data from 284 cities in China from 2006 to 2020 to investigate the impact of RETI on GISU. Our research findings reveal a positive association between RETI and GISU. Specifically, increasing 1 unit of RETI can promote GISU by 0.19 units. Moreover, we identify that environmental regulations, green finance, and human capital strengthen RETI’s stimulating effect on GISU. Notably, the study highlights that the positive influence of RETI on GISU is especially prominent in economically developed cities with a conducive innovation environment and those facing severe pollution challenges.