Present　work　systematically　investigates　the　kinetic　role　played　by　H2　molecules　during　Ni　surface　diffusion　and　deposition　to　generate　branched　Ni　nanostructures　by　employing　Density　Functional　Theory　(DFT)　calculations　and　ab　initio　molecule　dynamic　(AIMD)　simulations,　respectively.　The　Ni　surface　diffusion　results　unravel　that　in　comparison　to　the　scenarios　of　Ni(110)　and　Ni(100),　both　the　subsurface　and　surface　H　hinder　the　Ni　surface　diffusion　over　Ni(111)　especially　under　the　surface　H　coverage　of　1.5　ML　displaying　the　lowest　Ds　values,　which　greatly　favors　the　trapping　of　the　adatom　Ni　and　subsequent　overgrowth　along　the　(111)　direction.　The　Ni　deposition　simulations　by　AIMD　further　suggest　that　both　the　H2　molecule　(in　solution)　and　surface　dissociatively　adsorbed　atomic　H　can　promote　Ni　depositions　onto　Ni(111)　and　Ni(110)　facets　in　a　liquid　solution.　Moreover,　a　cooperation　effect　between　H2　molecules　and　surface　atomic　H　can　be　clearly　observed,　which　greatly　favors　Ni　depositions.　Additionally,　in　addition　to　working　as　the　solvent,　the　liquid　C2H5OH　can　also　interact　with　the　Ni(111)　surface　to　produce　the　surface　atomic　H,　which　then　favored　the　Ni　deposition.　Finally,　the　Ni　deposition　rate　predicted　using　the　deposition　constant　(Ddep)　was　found　to　be　much　higher　than　its　surface　diffusion　rate　predicted　using　Ds　for　Ni(111)　and　Ni(110),　which　quantitatively　verified　the　overgrowth　along　the　(111)　and　(110)　directions　to　produce　the　branched　Ni　nanostructures.