The　volcanic　rocks　LA-ICP-MS　zircon　U-Pb　ages　of　Cocien-Dowa　backland　depression　in　Jiwa　area,　Nima　County,　Tibet,　were　formed　around　120.3　similar　to　126.5Ma.　We　denied　the　understandings　of　predecessors　that　volcanic　rocks　were　Pliocene　Wuyu　Group　(N(2)wy)　and　Eocene　Pana　Formation　(E(2)p)　and　redefined　volcanic　rocks　as　Early　Cretaceous　Zenong　Group　(K(1)zn).　Rocks　which　have　the　characteristics　of　acid　volcanic　rocks　are　major,　and　intermediate-basic　volcanic　rocks　are　supplement.　Acid　rock　mostly　was　pyroclastic　rocks　and　lava　typical　rock　type　was　rhyolite　ignimbrite　and　rhyolite.　Basic　rock　mostly　was　basaltic　andesite　and　andesite-basalt　amygdaloidal　structure　development.　Plenty　of　welded　tuff　reflecting　the　geological　environment　mainly　was　the　continental　volcanic　eruptions.　These　rocks　are　rich　of　LREE,　with　an　apparent　negative　anomaly　of　Eu,　and　LILE　like　K,　Rb,　Th,　and　U　are　rich,　and　HFSE　like　Nb,　Ta,　P,　and　Ti　are　depleted.　Acid　volcanic　rocks　show　geochemical　features　similar　to　A-type　silicic　rocks　basic　volcanic　rocks　exhibit　geochemical　affinity　of　within-plate　basalts,　which　can　be　attributed　to　the　slab　break-off　at　that　time.　The　discovery　of　Early　Cretaceous　volcanic　rocks　in　south　of　the　Central　Lhasa　subterrane　pushes　the　position　of　magmatism　of　Late　Jurassic-Early　Cretaceous　southward　subduction　of　Bangong-Nujiang　70km　or　80km　to　the　south.　It　gives　new　constraint　information　to　the　geodynamic　background　of　Gangdese　belt　in　Early　Cretaceous　from　the　perspective　of　volcanic　rock.　It　seems　that　Early　Cretaceous　volcanic　rocks　in　Jiwa　area　that　happened　after　double　subduction　of　Bangong-Nujiang　Tethys　oceanic　crust　southward,　and　Yalung　Zangbo　oceanic　crust　northward.