Abstract：The late Permian–Triassic granites in southeastern China have important tectonic significance for the evolution of East Asia. Two Indosinian granites, which lithology is porphyritic syenite granite of Dashuang rock mass and porphyritic syenite and quartz syenite of Jingju rock mass，found in the town of Dashuang as well as eastern Jingju areas of Songyang in Zhejiang, have intruded into the Proterozoic basement. LA-ICP-MS zircon U-Pb age of Dashuang syenite is 241±2.1~229.6±2.5Ma, and LA-ICP-MS zircon U-Pb ages of Jingju porphyritic syenite and quartz syenite are 245.7 ± 1.8Ma and 241.2±2.7Ma, which indicate that these two rock masses are products of early Indosinian magmatism. For geochemical characteristic, the two granites are potassium-rich, high alumina, enriched in LREE and Rb, Th, U, K, depleted in Ba, Nb, Sr, P, Ti, close to the distribution patterns of A-type granites, which indicate that they are all aluminum A-type granite. A series of A-type granites distribution along the NE-trending fracture show extensional tectonic setting of southeastern China in early Indosinian, which may be caused by strike-slip conversion stretching after collision between SCB(South China block) and IB(Indochina block), making magma intrusion along the fault.