With　the　growing　tightening　constraints　of　ecological　environment,　managing　the　relationship　between　environmental　protection　and　economic　growth　has　become　a　vital　issue.　This　study　considered　China＇s　new　environmental　protection　law　(NEPL)　as　a　quasi-natural　experiment　to　evaluate　the　impact　of　environmental　regulations　on　enterprises’　total　factor　productivity　(TFP)　in　a　difference　in　differences　(DID)　framework　and　further　analyzed　the　internal　impact　mechanisms.　The　heterogenous　impacts　of　enterprises　with　different　characteristics　at　enterprise,　industrial,　and　regional　levels　are　investigated.　The　results　revealed　that　the　NEPL　significantly　hinders　enterprises’　TFP　and　the　effects　persist　for　two　years.　Further,　the　inhibition　on　enterprises’　TFP　mainly　results　from　tightening　financial　constraints　and　negative　impacts　on　technical　innovation　and　resource　allocation　efficiency.　When　considering　the　heterogeneity　at　enterprise,　industrial,　and　regional　levels,　state-owned　and　export　enterprises　and　enterprises　with　longer　establishment　times　and　better　cash　flow　situations　are　less　affected　by　the　implementation　of　the　NEPL.　Furthermore,　high　market　competitiveness　and　government　efficiency　are　conducive　to　easing　the　NEPL＇s　negative　impacts.　The　results　demonstrate　that　the　“win-win”　goal　between　environmental　protection　and　economic　growth　has　not　been　achieved　under　the　unified　standards　and　severe　sanctions.　Therefore,　it　is　vital　to　accelerate　market-oriented　reform　of　China＇s　environmental　regulations.　This　study　is　a　reexamination　of　Porter　Hypothesis　and　fills　the　gap　in　the　existing　literature　on　the　NEPL＇s　micro　influence　framework　on　enterprises’　TFP.　©　2020　Elsevier　Ltd