Achieving　efficient　economic　growth　in　a　low-carbon　manner　is　becoming　a　crucial　aspect　of　sustainable　development.　Meanwhile,　promoting　coordinated　development　to　achieve　synergistic　carbon　reduction　and　efficiency　enhancement　across　cities　from　a　holistic　perspective　holds　significant　practical　importance.　Based　on　panel　data　from　282　Chinese　cities　spanning　2005　to　2019,　this　study　employs　staggered　difference-in-differences　(DID)　and　spatial　Durbin　DID　models　to　investigate　the　direct　and　spatial　spillover　effects　of　China＇s　low-carbon　city　pilot　(LCCP)　policy　on　green　economic　efficiency.　The　findings　reveal　several　key　insights:　First,　the　LCCP　policy　significantly　enhances　green　economic　efficiency,　primarily　through　advancements　in　green　transportation,　employment,　and　technology.　Second,　a　notable　spatial　correlation　exits　in　the　green　economic　efficiency　of　Chinese　cities,　with　spatial　agglomeration　generally　trending　upward　over　time.　Third,　local　low-carbon　city　pilots　can　create　a　＂siphoning　effect＂　through　technology　and　population　concentration,　inhibiting　improvements　in　neighboring　areas　and　impeding　coordinated　sustainable　development　among　cities.　Therefore,　adopting　a　holistic　perspective,　establishing　coordination　mechanisms　among　cities,　and　promoting　the　optimal　overall　green　economic　efficiency　within　the　region　are　essential　for　effective　policy　outcomes.