Abstract: Based on geological, petrological and geochemical studies, the authors investigated Qinlingliang rapakiwi granite intrusion, porphyritic biotite rapakivi granite, porphyritic hornblende biotite rapakivi granite and medium-grained biotite monzonitic granite. LA-ICP-MS zircon U-Pb analysis suggests that Qinlingliang rapakiwi granite intrusion was formed in late Triassic(215.1±2.5Ma). Qinlingliang rapakiwi granite belongs to high-K calc-alkaline series with aluminous-peraluminous nature, and is characterized by enrichment of Rb, Th, K, Pb and Nd, depletion of Ba, Nb, Ta, La, P and Eu, and significant loss of Nb, Ta and P. In addition, this intrusion has moderate-low REE concentration and right-inclined distribution curve. The magma probably mainly originated from partial melting of the crust, and also had the characteristics of crust-mantle mixing. In combination with regional geological background, the authors hold that Qinlingliang rapakiwi granite intrusion probably originated from a post orogenic extension environment.