The Wulaxi granite is located in the southern region of Songpan—Garze orogenic belt, northern margin of Jianglang dome. The LA ICP MS analysis of zircons from the intrusion yield a weighted mean 206Pb/238U age of 159.31±0.9Ma. Albite and siderophyllite appear in rocks, which are belong to typical minerals of A type granite. The intrusion is characterized by high content of SiO2, Na2O and K2O, high FeOt/MgO and Ga/Al ratio, and low content TiO2, CaO and MgO. The granite is marked by a “sea gull” pattern of REE distribution, showing a relatively significant negative Eu anomaly, and rich high field strength elements such as Rb, Nb and Ga et.al, exhibiting remarkably negative Ba, Sr, P and Ti anomalies on the primitive mantle normalized trace element diagram. The intrusion shows high forming temperature through calculations of zircon saturation temperatures(ranging from 967℃ to 984℃) and lacked ancient nucleus in CL images of zircon. The intrusion also is relatively rich in aluminum with A/CNK=0.97~1.27(＞0.95) and NK/A=0.74～0.91(＜1 ). These characteristics resemble aluminous A type granite. In Zircon, n(176Hf)/n(177Hf) =0.282228~0.282749, average 0.282586, fLu/Hf = -0.99～-0.10, average -0.97, most εHf(t) are negative(-15.88～1.77), average -3.14, which indicates that the rock dominantly come from the crust, and probably originated from the partial melting of Proterozoic Metamorphic core complex in Jianglang dome.Combined with regional tectonic evolution, We suggest that the Wulaxi granite formed in an extensional setting after the continent—continent collision, and originated from the early Yanshanian decompressing melt of the thickening crust because of extensing relaxation after collision in the Songpan—Garze orogenic belt.