MnxCd1-xS　solid　solution　is　an　emerging　semiconductor　for　photocatalytic　water　splitting　with　a　tunable　bandgap.　However,　it　still　leaves　much　room　to　improve　the　photocatalytic　activity.　Herein,　we　modified　Mn-0.5Cd0.5S　with　noble　metal-free　NiSe　by　an　in-situ　hydrothermal　synthesis.　The　as-obtained　NiSe/Mn-0.5Cd0.5S　nanocomposites　exhibited　highly　efficient　photocatalytic　H-2　production　under　visible　light　and　the　highest　hydrogen　generation　rate　reaches　28.08　mmol/h/g,　which　is　higher　than　that　of　Mn-0.5Cd0.5S　(13.71　mmol/h/g)　and　1　wt%　Pt/Mn-0.5Cd0.5S　(24.22　mmol/h/g).　Through　the　detailed　analyses　of　UV-vis　DRS,　photoluminescence　(PL)　spectra,　time-resolved　photoluminescence　(TRPL)　and　photoelectrochemical　tests,　we　found　the　wellmatched　structure　between　NiSe　and　Mn-0.5Cd0.5S,　which　facilitates　the　charge　transfer　and　prolongs　the　lifetime　of　photo-induced　electrons,　and　thus　improves　photocatalytic　activity.