The Tangzang quartz diorite pluton, distributed in the western part of North Qinling and intruding into the volcano sedimentary rocks of Paleozoic Danfeng Group, is consist mainly of plagioclase, amphibole, quartz, alkali feldspar and biotite with the form age of 454Ma. Major and trace elements studies show that the pluton is characterized by typical adakite features with SiO2= 62.02％～64.26％；Al2O3=16.55%～17.45%，MgO=1.71%～2.09%, Sr = (1069～1296)×10-6（>400×10-6），Y = (11.6～13.81)×10-6 （<18×10-6），Yb = (0.96～1.14)×10-6（<1.9×10-6），Sr/Y=80.98～108.19（>40）， enriched LREE and depleted HREE, lack negative Eu anomalies（LREE/HREE=17.72~25.82；LaN/ YbN=44.56～53.85；δEu＝0.82～1.0）. Primitive manlte normalized trace elements patterns reveal that LILE (K，Th，Rb，Ba，Sr) is enriched, but HFSE (Ta，Nb，Y，Yb) are depleted compared with adjacent elements, which is similar to that of typical adakite. The research also showed that the pluton is characterized with f Na2O (4.99%～6.91%), Na2O＞K2O, Mg#(0.59～0.63), A/CNK(0.82～1.01) and σ(4.24～2.24), suggesting that the Tangzang quartz diorite pluton belongs to Narich, magnesium adakitic rocks. Parent magma of the adakitic rocks originated from partial melting of the subducted ocean slab of the Qinglin Shangdan oceanic plate toward north, and reacted with the mantle when twhen the magma was ascending. The discovery of the Tangznag adakitic rocks in the west segment of North Qinling provides new evidence for studying Paleozoic tectonic evolution in Qinling Mts.