The　supergiant　Shuangjianzishan　(SJS)　Ag-Pb-Zn　deposit,　located　in　the　southern　Great　Xing＇an　Range　(SGXR),　is　the　largest　Ag　deposit　in　China.　The　SJS　deposit　can　be　divided　into　two　ore　blocks:　the　Shuangjianzishan　ore　block　and　the　Xinglongshan　ore　block.　Given　the　importance　of　the　Xinglongshan　ore　block　in　the　SJS　deposit,　our　work　is　focused　on　the　Xinglongshan　ore　block.　The　vein　orebodies　in　the　Xionglongshan　ore　block　mainly　occur　in　the　NW-,　NNW-,　and　NNE-trending　fault　zones,　and　its　mineralization　is　mainly　related　to　a　deep　concealed　syenogranite.　Here,　we　present　new　geochronology,　isotope　geochemistry,　and　fluid　inclusion　data　for　the　Xinglongshan　ore　block　and　provide　additional　insights　into　the　metallogenic　mechanism　of　the　deposit.　The　dating　results　show　that　the　syenogranite　related　to　the　mineralization　formed　at　approximately　137　Ma,　which　is　coherent　with　some　previous　age　determinations　in　sulfides　from　the　ore　deposit.　The　mineralization　of　the　Xinglongshan　ore　block　can　be　divided　into　four　stages:　sphalerite-arsenopyrite-pyrite-chalcopyrite-quartz　stage　(stage　I),　sphalerite-galena-pyrite-silver-bearing　mineral-quartz　stage　(stage　II),　sphalerite-galena-silver-bearing　mineral-quartz-calcite　stage　(stage　III),　and　weakly　mineralized　quartz-calcite　stage　(stage　IV).　Four　types　of　fluid　inclusions　(FIs)　have　been　identified　within　quartz　and　calcite　veins:　liquid-rich,　gas-rich,　pure-liquid,　and　pure-gas　FIs.　The　homogenization　temperatures　in　the　four　stages　exhibit　a　gradual　decrease,　with　stage　I　ranging　from　253　to　302　degrees　C,　stage　II　from　203　to　268　degrees　C,　stage　III　from　184　to　222　degrees　C,　and　stage　IV　from　153　to　198　degrees　C,　respectively.　The　salinity　for　stages　I,　II,　III,　and　IV　falls　within　the　ranges　of　3.4-6.6　wt%　NaCl　eqv.,　2.6-7.2　wt%　NaCl　eqv.,　2.9-7.0　wt%　NaCl　eqv.,　and　1.2-4.8　wt%　NaCl　eqv.,　respectively,　indicative　of　a　low-salinity　ore-forming　fluid.　The　delta　18Owater　and　delta　D　values　of　the　ore-forming　fluid　span　from　-13.9　parts　per　thousand　to　7.4　parts　per　thousand　and　-145　parts　per　thousand　to　-65　parts　per　thousand,　with　delta　13CV-PDB　values　between　-11.0　parts　per　thousand　and　-7.9　parts　per　thousand.　These　values　suggest　that　the　ore-forming　fluid　predominantly　originated　from　a　mixture　of　magmatic　and　meteoric　water.　The　206Pb/204Pb,　207Pb/204Pb,　and　208Pb/204Pb　ratios　of　sulfides　range　from　18.278　to　18.361,　15.530　to　15.634,　and　38.107　to　38.448,　respectively.　These　ratios　imply　that　the　ore-forming　material　was　primarily　derived　from　the　Early　Cretaceous　granitic　magma,　which　resulted　from　the　mixing　of　depleted　mantle-　and　crustal-derived　magmas.　The　fluid　mixing　was　the　dominant　mechanism　for　mineral　precipitation.　The　Xinglongshan　ore　block　belongs　to　a　magmatic-hydrothermal　vein-type　deposit　related　to　the　Early　Cretaceous　syenogranite,　and　the　Shuangjianzishan　ore　block　belongs　to　an　intermediate　sulfidation　epithermal　deposit　related　to　coeval　subvolcanic　rocks.　The　Ag-Pb-Zn　mineralization　at　Shuangjianzishan　is　genetically　related　to　the　Early　Cretaceous　volcanic-intrusive　complex.