Various　Ni　supported　on　active　carbon　(Ni/AC)　catalysts　were　acquired　by　reduced　at　different　temperatures,　among　which　Ni/AC-500　possesses　the　smallest　particle　sizes　of　metallic　Ni　species,　favoring　to　more　active　sites　exposed　on　the　catalyst　surface,　and　the　suitable　content　of　metallic　Ni0,　implying　the　high　hydrogenolysis　activity　obtained.　Additionally,　the　highest　mesoporous　volume　of　Ni/AC-500　promotes　the　diffusion　of　large　molecules　from　lignin　depolymerization.　Therefore,　Ni/AC-500　exhibits　the　higher　lignin　conversion　and　yields　of　liquid　bio-oil　and　monomers,　but　the　lower　yield　of　bio-char　in　lignin　hydrodepolymerization　due　to　its　higher　hydrogenolysis　activity　compared　with　other　catalysts.