Rational design of catalytic sites to activate the inert N≡N bond is of paramount importance to advance N2 electroreduction.Here,guided by the theoretical predictions,we construct a NiFe layered double hydroxide (NiFe-LDH) nanosheet catalyst with a high density of electron-deficient sites,which were achieved by introducing oxygen vacancies in NiFe-LDH.Density functional theory calculations indicate that the electron-deficient sites show a much lower energy barrier (0.76 eV) for the potential determining step compared with that of the pristtne NiFe-LDH (2.02 eV).Benefiting from this,the NiFe-LDH with oxygen vacancies exhibits the greatly improved electrocatalytic activity,presenting a high NH3 yield rate of 19.44 pg·h-1·mgcat-1,Faradaic efficiency of 19.41％ at-0.20 V vs.reversible hydrogen electrode (RHE) in 0.1 M KOH electrolyte,as well as the outstanding stability.The present work not only provides an active electrocatalyst toward N2 reduction but also offers a facile strategy to boost the N2 reduction.