Abstract: Abstract：High-precision SHRIMP U-Pb dating was performed on zircon from quartz diorite and diabase in the Xinqiao Cu-S-Fe-Au deposit， Tongling ore district， Anhui. Zircon from quartz diorite yielded a 206Pb/238U age of (140.4±2.2) Ma， while the zircon age of diabase is relatively complex. Several Proterozoic zircon grains were found in diabase， which yielded 207Pb/206Pb ages of (2 261±14) Ma， (1 612±8) Ma， (919±12) Ma and (831±17) Ma. In addition， there is also a group of Early Paleozoic zircon grains， whose 206Pb/238U age is (443±13) Ma. The above new data give the information of the possible existence of Proterozoic basement in this district， and Yanshanian magmatism is of great significance for mineralization in the district.