A　large　amount　of　granites　widely　distributes　in　Halasen　area　in　the　East　Kunlun　Mountains.　The　study　of　the　granites　not　only　help　us　to　understand　the　tectono-magmatic　evolution　history　of　East　Kunlun　orogenic　belt　in　the　Late　Paleozoic　and　Early　Mesozoic,　but　also　provides　constraints　for　the　subduction　and　closed　time　limit　of　the　Paleo-Tethys　Ocean.　In　this　paper,　we　constrain　geochronology　and　petrogenesis　of　the　Halasen　granites　by　zircon　U-Pb　dating　and　geochemical　analyses.　The　LA-ICP-MS　U-Pb　analyses　show　that　the　formation　ages　of　K-feldspar　granite　and　fine-grained　monzogranite　are　239.2±1.7　Ma　(MSWD=0.19)　and　232.4±1.2　Ma　(MSWD　=0.76),　respectively,　which　are　the　products　of　the　Middle　Triassic　granitic　magmatism.　The　geochemistry　data　show　that　granites　are　high-potassium　calcalkaline-shoshonite,　peraluminous　rock　which　is　characterized　by　high　silicon　and　aluminum,　enriched　alkali,　low　titanium,　as　well　as　enriched　light　rare　earth　elements　(LREE)　and　large　ion　lithophile　elements　(LILE,　e.　g.,　K,　Th　and　Rb),　and　depleted　in　high　field-strength　elements　(HFSE,　e.　g.,　Nb,　Ti,　P,　and　Ta)　with　obvious　Eu　negative　anomaly　(the　value　of　δEu　is　between　0.27　and　0.65).　Halasen　granites　belong　to　highly　fractionated　I-type　granite.　It　is　suggested　that　the　Halasen　granites　were　most　likely　derived　from　parental　magma　by　mixing　of　depleted　mantle-derived　magma　and　induced　crustal-melted　felsic　magma　in　the　deep　crust,　and　then　suffered　further　differentiation　during　magma　ascent.　The　subduction　of　the　East　Kunlun　Paleo-Tethys　Ocean　lasted　to　the　Early　Triassic,　and　the　Middle　Triassic　witnessed　the　intracontinental　collision.　©　2018,　Editorial　Department　of　Earth　Science.　All　right　reserved.