Electrolysis　of　seawater　is　currently　a　promising　technology　for　efficient　green　hydrogen　production　and　solving　the　energy　crisis.　Urea　oxidation　reaction　(UOR)　has　a　low　thermodynamic　onset　potential,　which　is　an　effective　reaction　to　replace　the　oxygen　evolution　reaction　(OER)　in　overall　seawater　splitting　and　avoid　toxic　hypochlorite　generation.　In　this　paper,　we　report　sulfur-doped　NiFe　LDH　with　ultrathin　nanoflower　morphology　on　the　surface　of　three-dimensional　nickel　foam　(NF)　loaded　with　Ti3C2Tx　MXene　by　the　two-step　electrodeposition　method　(S-NiFe　LDH/MXene@NF).　The　catalytic　performance　of　electrolytic　seawater　is　boosted　by　the　synergistic　effect　of　the　abundant　interface　between　Ti3C2Tx　MXene　and　sulfur-doped　NiFe　LDH,　which　promotes　electron　transfer.　S-NiFe　LDH/MXene@NF　exhibited　electrocatalytic　performance　values　of　1.578　and　1.437　V　(vs　RHE)　for　OER　and　UOR　at　500　mA　cm(-2),　respectively,　and　an　overpotential　of　336　mV　for　the　hydrogen　evolution　reaction　(HER)　at　500　mA　cm(-2)　in　an　alkaline　seawater　electrolyte.　As　a　bifunctional　electrode,　it　can　achieve　a　current　density　of　500　mA　cm(-2)　at　2.027　V　with　great　stability.　The　in　situ　Raman　detection　of　surface　recombination　of　the　S-NiFe　LDH/MXene@NF　electrode　in　the　UOR　demonstrates　that　Ti3C2Tx　MXene　accelerates　the　formation　of　the　active　species　NiOOH　on　the　electrode　surface　and　facilitates　the　lattice　disturbance　of　NiOOH.　This　helps　to　increase　the　catalytic　activity　of　urea-assisted　overall　seawater　splitting.