This paper presents the petrology and geochemistry of the middle-late Jurassic adakitic granites (165~153 Ma) in the southeast edge of Dayao Mountain in the southwestern part of the Qinhang junction zone, and discusses its characteristic attribute of adakitic and TTG rocks. The SiO₂ content of the rocks varies from 63.76% to 72.13%. The rocks show adakitic features with high Al₂O₃(≥ 15%), low MgO(<3%), depleted HREE, positive Eu anomaly (some of them are weakly negative Eu anomaly), low Y(≤ 18×10^-6) and Yb(≤ 1.9×10^-6), high Sr(>300×10^-6) and Sr/Y(>20). Combined with the study of regional tectonic evolution, it is considered that the Jurassic adakitic granite was formed in the intracontinental extensional tectonic setting, which is the product of partial melting of the thickened lower crust in the continental intraplate (uplift area), and belongs to the intracontinental non-arc environment I-type granite. The Jurassic adakitic granites are similar to the two high-pressure TTG subclasses of low-Mg andesite/diorite series (LMA) and Mg andesite/diorite series (MA). They are the inheritance characteristics of arc-type rocks melting in the lower crust of the Paleozoic subduction accretion zone, and belong to non-subduction genesis, which has nothing to do with the Mesozoic Paleo-Pacific subduction slab melting process. They are highly coincident with the early Paleozoic subduction accretion zone in the southern margin of Dayao Mountain, and closely adjacent to the early Paleozoic TTG intrusive rock assemblage, suggesting that they may have originated from the partial melting of basaltic rocks in the oceanic subduction zone or the lower crust of the continental margin arc in the early Paleozoic, so they have the characteristic attributes of oceanic subduction.