The　exploration　of　efficient　electrocatalysts　is　the　central　issue　for　boosting　the　overall　efficiency　of　water　splitting.　Herein,　pertinently　creating　active　sites　and　improving　conductivity　for　metal-organic　frameworks　(MOFs)　is　proposed　to　tailor　electrocatalytic　properties　for　overall　water　splitting.　An　Ni(II)-MOF　nanosheet　array　is　presented　as　an　ideal　material　model　and　a　facile　alkali-etched　strategy　is　developed　to　break　its　Ni-O　bonds　accompanied　with　the　introduction　of　extra-framework　K　cations,　which　contribute　to　creating　highly　active　open　metal　sites　and　largely　improving　the　electrical　conductivity.　As　a　result,　the　assembled　defect-Ni-MOF||defect-Ni-MOF　electrolyte　cell　delivers　a　lower　and　stable　voltage　of　1.50　V　at　10　mA　cm(-2)in　alkaline　medium　for　overall　water　splitting,　comparable　to　the　combination　of　iridium　and　platinum　as　benchmark　catalysts.