Data　factor　marketization　(DFM)　can　fully　leverage　the　multiplier　effect　of　data　and　provide　impetus　for　China　＇s　carbon　emission　efficiency　(CEE)　improvement.　Drawing　from　the　panel　data　across　282　Chinese　cities　from　2011　to　2021,　this　research　takes　the　establishment　of　data　trading　platforms　as　the　quasi-natural　experiment,　and　innovatively　uses　the　double　machine　learning　(DML)　model　to　study　the　impact　of　DFM　on　CEE　and　its　mechanisms.　The　findings　indicate　that:　(1)　DFM　has　a　strong　favorable　impact　on　CEE.　Furthermore,　this　conclusion　remains　valid　following　a　series　of　robustness　tests　such　as　adjusting　samples　and　changing　models.　(2)　DFM　can　influence　CEE　by　accelerating　digital　finance　development,　improving　technological　innovation　level　and　promoting　industrial　structure　towards　the　direction　of　advanced　development　(3)　The　effect　of　DFM　has　obvious　regional　heterogeneity.　It　is　more　significant　for　non-resource-based,　high　administrative　level,　low-intensity　environmental　regulation　and　economically　developed　cities.　This　study　quantifies　the　promotion　effect　of　the　DFM　on　CEE,　and　provides　important　experience　and　enlightenment　for　comprehensively　deepening　the　construction　of　data　resource　system　and　achieving　sustainable　development.　©　2024　Elsevier　Ltd