U-Pb ages and trace elements of zircons from porphyritic granite of Machangqing complex were analyzed by the LA-ICP-MS method. As revealed by the cathodoluminescence (CL) images, all the zircons from porphyritic granite have the oscillatory zoning. REE patterns of the analyzed zircons are characterized by significantly high heavy rare earth elements (HREE), depleted light rare earth elements (LREE), obviously positive Ce anomaly and moderately negative Eu anomaly. Muscovites of contact metasomatic gold mineralization from the Luandongshan ore block yield the 40Ar/39Ar age of (35.25±0.36) Ma.Muscovites of hydrothermal vein gold mineralization from the Rentouqin-Jinchangqin ore block yield the 40Ar/39Ar age of (35.35 ±0.32) Ma. These ages show that porphyry type copper-molybdenum mineralization, contact metasomatic gold mineralization and hydrothermal vein gold mineralization are products of the same tectonic-magmatic-hydrothermal ore-forming system.