The Cunqian copper polymetallic deposit is an important porphyry-skarn deposit along eastern Qinhang metallogenic belt. The LA-ICP-MS technique was used in this study, and U-Th-Pb isotopic analysis was made for zircons from the ore-bearing plagioclase granite porphyry, with the petrogenic age obtained being(169.3 ± 1.1)Ma. This petrogenic age of the ore-bearing rock body is very close to ages of Dexing granodiorite porphyry, Yinshan quartz porphyry, Lengshuikeng granite porphyry and Tongcun granite-porphyry, suggesting that an event of large-scale magmatic emplacement and mineralization took place in 175~156 Ma..