Hypabyssal porphyries associated with porphyry copper deposits are widely distributed in Zhongdian island arc in the northwest of Yunnan Province. The LA-ICPMS zircon U-Pb method is used to date the formational age of the porphyries in western and eastern side of the Zhongdian island arc. Zircons separated from Xuejiping ore-bearing porphyry in the western side of Zhongdian yielded mean 206Pb/238Pb ages of (213.4±1.5) Ma. Meanwhile zircons separated from Qiansui quartz dioritic porphyrite in the eastern side of Zhongdian yielded mean 206Pb/238Pb ages of (217.1±1.5) Ma. These ages are consistent with those of high-precision zircon geochronology reported by other porphyries in this area, which indicate that they are coeval and without obvious different ages between western and eastern side porphyries in the Zhongdian island arc.