The Dapingzhang Cu-polymetallic deposit is a typical VHMS (volcanics-hosted massive sulfides) deposit related to intermediate-acid rocks. The granodiorite porphyry that intruded into the ore-bearing volcanic series is large in size, but its research has been very insufficient. Based on field investigation, the authors studied systematically the formation characteristics, petrology, petrochemistry and chronology of the intrusive body. The results show that the granodiorite porphyry and the volcanic rocks have typical intrusive contact relationship. The granodiorite porphyry, belonging to calc-alkaline high calcium volcanic series, shows volcanic arc granite characteristics as evidenced by distribution patterns of trace elements and rare earth elements. LA-ICP-MS zircon U-Pb age of the granodiorite porphyry is 401.0±1.7 Ma, suggesting early stage of Early Devonian period. This means that the granodiorite porphyry was not formed in the Indosinian period. It is also shown that the age of the volcanics and the VHMS deposit should be early Devonian, rather than late Devonian-early Carboniferous.