The Qingcaoshan granitic pluton, located in the Zhapu-Duobuza magmatic arc in southern Qiangtang, consists of granite porphyry and quartz monzonitic porphyry. However, the age and genesis are not studied due to absence of geochemical and geochronological data. The weighted average 206Pb/238U age of 122±1 Ma (MSWD=3.9) for quartz monzonitic porphyry and 114.6±1.2 Ma (MSWD=1.1) for granite porphyry is present by LA-ICPMS and SHRIMP zircon U-Pb dating. The intrusion have minor muscovite and cordierite, no hornblende. The granitic pluton is characterized by enriched Al (A1₂O₃: 14.81%-15.86%), depleted Ca (CaO: 1.10%-2.44%), and high content of alkali (K₂O+Na₂O: 6.86%-8.80%). Father more, it is also characterized by ASI of 1.1 (A/CNK: 1.06-1.20), corundum (1.20%-2.86%) and absence of diopside showed through CIPW calculation, which are indicative of peraluminous sub-alkaline S-type graniten. The intrusive rock is relatively enriched in large ion lithophile elements (Rb, Th, U, K, La, Ce) and depleted in high field strength elements (Ta, Nb, P, Ti, Y), and exhibits LREE-enriched ((La/Yb)N: 3.24-16.20) with right-inclined REE distribution patterns. A synthesis of all these characteristics indicates that the Qingcaoshan granitic pluton was probably derived from partial melting of greywacke components in the upper crust as a result of norward subduction of the Bangong Co-Nujiang oceanic crust towards the Qiangtang block.