Abstract: To explore the impact of China's green technology innovation on carbon productivity and its spatial agglomeration and spillover effects. From 2000 to 2019, the panel data of 30 provinces in China were selected to construct a spatial Dubin model, and the multiple mediating effect model was used to analyze the transmission mechanism of green technology innovation on carbon productivity through industrial structure upgrading, circular agricultural development and transportation substitution. The results show that: (1) the carbon productivity of each province is autocorrelation in space, and has the distribution characteristics of "high east and low west, high south and low north"; (2) Green technology innovation has a significant effect on local carbon productivity, but the spillover effect is not significant; (3) The total effect of the three mediating variables was industrial structure upgrading> transportation substitution > circular agriculture development, circular agricultural development and transportation substitution and industrial structure upgrading were different, but there was no difference in the intermediary role between transportation substitution and industrial structure upgrading.

Keywords: carbon productivity; green technology innovation; industrial structure upgrading; circular agriculture development; Transportation substitution