Zircon U-Pb SIMS dating of porphyritic monzogranite in this study indicates that the intrusions intensively exposed in the Tinggong ore district are Eocene （48.88±0.53） Ma instead of Miocene in age, and constitute a part of the Gangdise batholiths. Further studies indicate that the mineralization-unrelated porphyritic intrusions occur not only in Tinggong but also in ore deposits as Chongjiang, Bairong and Gangjiang in the ore concentration area. Thus, the relationship between the porphyritic intrusions and Cu-Mo mineralization should be adequately considered in the upcoming exploration in this area.