Innovation　and　carbon　neutrality　are　hot　topics　nowadays　and　are　important　issues　related　to　development　quality,　efficiency,　and　long-term　sustainability.　The　purpose　of　this　paper　was　to　analyze　the　impact　of　innovation-driven　policy　on　reducing　carbon　emission　intensity.　Using　urban　panel　data　from　2003　to　2018,　this　paper　constructed　a　time-varying　difference-in-difference　model　based　on　the　natural　experiment　of　national　innovative　city　pilot　policy　and　systematically　examined　the　specific　effects　and　mechanisms　of　innovation-driven　policy　on　reducing　carbon　emission　intensity.　It　was　found　that　the　innovation-driven　policy　represented　by　the　national　innovative　city　pilot　policy　can　significantly　reduce　the　carbon　emission　intensity　in　China,　and　this　result　was　still　valid　after　various　robustness　tests.　The　mechanism　analysis　showed　that　a　reduction　in　carbon　emission　intensity　was　mainly　achieved　by　innovation-driven　promotion　of　green　production　technology　progress　and　improvements　in　energy　use　efficiency.　Further　heterogeneity　analysis　showed　that　the　policy　had　a　more　significant　carbon　reduction　effect　in　cities　with　a　strong　innovation　capability,　large　size,　and　low　level　of　industrial　structure.　These　research　conclusions　provide　useful　references　for　further　understanding　of　the　economic　and　social　benefits　of　innovation-driven　policy　and　effectively　unleashing　the　carbon　emission　reduction　effects　of　innovation-driven　policy　and　promoting　sustainable　development.