The quartz-dioritic intrusions in Tongguanshan of Tongling district, Anhui Province, are spatially and temporally associated with copper mineralization. Sensitive High Resolution Ion Microprobe (SHRIMP) U-Pb zircon dating of quartz diorites from Xiaotongguanshan in the Tongling ore district indicates felsic intrusive activity at 139～133 Ma, which also represents the copper mineralization epoch. Some of the zircon grains yield 207Pb/206Pb ages of (2 670～2 025) Ma, implying the involvement of the Precambrian metamorphic basement in the formation of quartz diorites. The presence of such zircon grains in these quartz diorites suggests that either the parental magmas were assimilated by basement rocks during the ascent of magma or the lower/middle crustal rocks served as one of the important components during the melting process.