There is a suite of acid rocks consisting of rhyolitic breccia, rhyolite and perlite in Shuidong area, Xuancheng City, in the middle-lower reaches of the Yangtze River. In this paper, the authors reported detailed studies of the LA-ICP-MS zircon U-Pb dating, major elements, trace elements, whole-rock Nd isotopic compositions and zircon Hf isotopic compositions of the acid rocks. The results of zircon LA-ICPMS U-Pb dating are 133.2±0.8 Ma (rhyolitic breccia), 133.4±0.8 Ma (rhyolite) and 131.5±0.9 Ma (perlite), respectively. Geochemical researches indicate that the acid volcanic rocks are rich in silica (SiO₂=72.51%~81.79%), K (K₂O/Na₂O=2.04~14.93, 6.72 on average) and poor in calcium (CaO=0.19%~1.57%) and magnesium (MgO=0.06%~0.29%), implying a typical high-K calc-alkaline to shoshonitic series with weakly peraluminous features (A/CNK=1.02~1.24). The rocks are enriched in LREE, LILEs (Rb, Ba, Th and K) but depleted in HFSE, especially Nb, Sr, P and Ti. The Eu/Eu^* ratios vary from 0.44 to 0.60, with most rocks having prominent negative Eu anomalies. Based on integration of the geological characteristics of the study area, the authors proposed that the acid rocks were formed by anatexis of the Neoproterozoic middle and upper crust. The petrogenetic event probably occurred in an intraplate extensional environment after the subdutiion of the Pacific Plate at~135 Ma.