The　piezoelectricity　of　MoS2　only　exists　in　monolayer　and　odd-number　layers,　owing　to　the　inversion　symmetry　of　the　even　number　layers,　which　limits　the　efficient　utilization　and　mass　synthesis　of　MoS2.　Herein,　the　structure　of　MoS2　is　adjusted　by　oxygen　doping,　which　could　break　the　layer-dependent　piezoelectricity　and　induce　out-of-plane　polarization.　This　endows　O-doped　MoS2　the　free　layer-dependent　and　enhanced　piezoelectricity.　Benefiting　from　the　optimized　piezoelectricity,　higher　concentration　of　carriers,　higher　Hall　mobility　and　lower　resistivity,　the　O-doped　MoS2　exhibits　an　improved　activity　of　piezocatalytic　H2　production　from　pure　water,　and　the　corresponding　H2　evolution　rate　reaches　up　47.75　μmol·h−1·g−1.　Under　the　same　conditions,　the　hydrogen　production　rate　of　MoS2　is　only　20.19　μmol·h−1·g−1.　This　work　not　only　provides　a　new　strategy　for　modulating　piezoelectricity　of　transition　mental　dichalcogenides,　whose　bulk　materials　are　non-piezoelectric,　but　also　breaks　new　ground　for　developing　high-efficiency　piezocatalysts.　©　2021