Zijinshan　ore　field　is　located　in　the　eastern　part　of　South　China　fold　system,　belonging　to　the　Southwest　Fujian　depression,　where　develops　many　large　and　super-large　epithermal　Au-Cu-Ag　deposits　which　are　closely　related　with　magmatic　activities.　The　study　in　this　paper　is　based　on　a　detailed　research　of　the　fine-grained　biotite　granite　in　the　southeastern　ore　section　including　field　geological　survey　and　petrography,　zircon　rare　earth　elements,　in-situ　zircon　U-Pb　chronology　and　Hf　isotope　et　al..　The　LA-ICP-MS　zircon　U-Pb　dating　shows　that　the　206Pb/238U-207Pb/235U　correlated　age　of　the　biotite　granite　is　109.5±1.9　Ma　(MSWD=0.74,　N=16),　and　206Pb/238U　weighed　age　is　107.44±0.94　Ma(MSWD=1.06,　N=16),　and　the　two　ages　are　within　the　error　range.　According　to　zircon　REE　and　magmatic　oscillatory　zoning　characteristics　and　the　Th/U　ratios,　the　age　can　represent　the　rock　crystallization　age,　which　suggests　fine-grained　biotite　granite　emplaced　in　the　Early　Cretaceous　of　the　Yanshanian　epoch.　The　Hf　isotope　initial　ratio　ΕHf(t)　values　are　negative,　ranging　from　-4.99　to　-1.06　(mean　value　is　-2.99).　Two　stage　Hf　model　ages　(tDM2)　range　from　1　233.7　Ma　to　1　485.4　Ma　(mean　value　is　1　362.4　Ma).　The　ΕHf(t)　and　Hf　values　show　small　variations　in　distribution,　which　implies　that　magmatic　rocks　having　a　more　uniform　zircon　Hf　isotope　composition.　The　in-situ　zircon　U-Pb　chronology　and　Hf　isotope　show　time　and　source　characteristics　of　Early　Cretaceous　magmatic　activity　in　south-western　part　of　Fujian　Province,　which　results　from　the　evolution　of　the　extension　and　thinning,　and　crust-derived　magma　substance　involved　from　lithosphere　are　closely　related.　In　this　paper,　it　provides　new　evidence　on　the　mineralization　and　tectonic　evolution　of　the　Zijinshan　ore　field.　©　2019,　Editorial　Department　of　Earth　Science.　All　right　reserved.