There are plenty of granite porphyry stocks and dikes, spatially coincide with the secondary faults associated with the NS-striking normal faults, intruded into the Linzizong volcanic suits located in the northern margin of the Nanmuling basin, Lhasa block. This paper carried out detailed field investigation, zircon LA -ICP-MS U-Pb dating, LuHf isotope and element geochemical research for the granite porphyry. The results show that the granite porphyry are high silicon alkaline series, with SiO2= 68.31 ~ 71.34 %, K2O = 4.52 ~ 4.96 %, K/Na = 1.53 ~ 1.9, and Al index (A/CNK) = 0.98 ~ 1.23. The granite porphyry is characterized by high LILE and low HFSE contents, in addition, it has high (La/Yb)N(21.59 ~ 36.81) and Sr/Y (Sr/Y = 15.59 ~ 38.10) values. Zircon LA -ICP -MS U -Pb age of the granite porphyry is 12.23 ± 0.12 Ma and εHf(t) values is -0.6 ~ +4.0. Petrological and geochemical characteristics indicate the granite porphyry was originated from the partial melting of juvenile lower crust, and garnet — rutile — hornblende remains in source area, with the fractional crystallization of alkali feldspar during the invasion. The granite porphyry formed in Miocene, consistent with the deveopment of North — South striking ridge, and its composition similar to highstrontium lowyttrium porphyry and the potassic rocks in the southern part of the Lhasa block, which is formed associated with an extension setting during the collision of India - Eurasia.