Direct　oxidation　of　methane　to　methanol　(DMTM)　is　a　big　challenge　in　C-1　chemistry.　We　present　a　continuous　N2O-DMTM　investigation　by　simultaneously　introducing　10　vol　%　H2O　into　the　reaction　system　over　Cu-BEA　zeolites.　Combining　a　D2O　isotopic　tracer　technique　and　ab　initio　molecular　dynamics　(AIMD)　simulation,　we　for　the　first　time　demonstrate　that　the　H2O　molecules　can　participate　in　the　reaction　through　a　proton　transfer　route,　wherein　the　H2O　molecules　can　build　a　high-speed　proton　transfer　bridge　between　the　generated　moieties　of　CH3-　and　OH-　over　the　evolved　mono(mu-oxo)　dicopper　([Cu-O-Cu](2+))　active　site,　thereby　pronouncedly　boosting　the　CH3OH　selectivity　(3.1　-＞　71.6　%),　productivity　(16.8　-＞　242.9　mu　mol　g(cat)(-1)　h(-1))　and　long-term　reaction　stability　(10　-＞　70　h)　relative　to　the　scenario　of　absence　of　H2O.　Unravelling　the　proton　transfer　of　H2O　over　the　dicopper　[Cu-O-Cu](2+)　site　would　substantially　contribute　to　highly　efficient　catalyst　designs　for　the　continuous　DMTM.