The Machangqing complex is composed of early syenitic-monzonitic porphyry and late granite-porphyry. Geochemically, they are similar in major and trace element characteristics, and are characterized by relatively low TiO-2 ({<0.5}) and P-2O-5 ({<0.4}) and high alkali contents (K-2O+Na-2O > 8%), with K-2O/Na-2O>1, the absence of significant Eu anomaly and pronounced negative anomalies in Nb, Ta, Ti, and enrichment in large-ion lithophile elements and light rare-earth elements. Zircon U-Th-Pb ELA-ICP-MS age determination of the Machangqing complex has revealed two discrete igneous events. The syenitic-monzonitic porphyry has an age of {35.6}± 3 Ma, MSWD={2.80}; the granite-porphyry, {35.0}±{0.2} Ma, MSWD={2.91}. The lifespan of magmatic activities of the Machangqing complex associated with Cu+Mo mineralization is about {0.6} Ma. The late-stage ore-bearing granite-porphyry has higher Ce~(4+)/Ce~(3+) ratios (264) than the early-stage barren syenitic-monzonitic porphyry (102). The increase of zircon Ce~(4+)/Ce~(3+) ratios from the early-to late-stage porphyries indicates that the oxidation state of the magmas associated with copper mineralization increases with time. The Machangqing complex is composed of early syenitic-monzonitic porphyry and late granite-porphyry. Geochemically, they are similar in major and trace element characteristics, and are characterized by relatively low TiO-2 ({<0.5}) and P-2O-5 ({<0.4}) and high alkali contents (K-2O + Na-2O> 8%) with K- 2O / Na- 2O> 1, the absence of significant Eu anomaly and pronounced negative anomalies in Nb, Ta, Ti , and enrichment in large-ion lithophile elements and light rare-earth elements. Zircon U-Th-Pb ELA-ICP-MS age determination of the Machangqing complex has revealed two discrete igneous events. The syenitic-monzonitic porphyry has an age of { 35.6} ± 3 Ma, MSWD = {2.80}; the granite-porphyry, {35.0} ± {0.2} Ma, MSWD = {2.91}. The lifespan of magmatic activities of the Machangqing complex associated with Cu + Mo mineralization is about { 0.6} Ma. The late-stage ore-bearing granite-porphyry has higher Ce ~ (4 +) / Ce ~ (3+) ratios (264) than the early-stage barren syenitic-monzonitic porphyry e of zircon Ce ~ (4 +) / Ce ~ (3 +) ratios from the early-to late-stage porphyries indicates that the oxidation state of the magmas associated with copper mineralization increases with time.