The Neoproterozoic Xiuning Formation and the underlying Shangshu Formation, located on the northern side of the Jiangshan-Shaoxing fault, are significant stratigraphic unites in the eastern Jiangnan Orogen, South China. They record Neoproterozoic tectonic evolution information and provide crucial evidence for regional stratigraphic correlation and tectonic evolution. In this study, microscopic characteristics, zircon CL images, and LA-ICP-MS U-Pb geochronological data are presented for sandstone and tuff from the Xiuning Formation and Shangshu Formation, respectively. The microscopic characteristics of the sandstone and the CL images of the zircons show that the detrital particles and zircons of the sandstone predominantly exhibit angular and subangular, revealing a short-range transportation of the source, while the tuff of the Shangshu Formation exhibit plagioclase phenocrysts and zircons with zonal and rhythmic structures, representing magmatic origin. The detrital zircon U-Pb ages from the Xiuning Formation are primarily concentrated between 843 Ma and 718 Ma, with six ages from the Mesoproterozoic to Paleoproterozoic. The weighted mean U-Pb age of zircons derived from the tuff of the Shangshu Formation is 847±6.7 Ma (n=18，MSWD=1.8). Combined with the published data from eastern part of Jiangnan Orogen, it is inferred that the beginning and end deposition ages of Xiuning Formation are ~785 and ~725 Ma, respectively, while the underlying Shangshu Formation was formed during 845~785 Ma. The Shangshu Formation records magmatic activities at approximately 845, 825, and 800-785 Ma, reflecting multiple volcanic-depositional cycles in the study area. During the period of 850~785 Ma, the Yangtze and Cathaysian blocks underwent a sequence of subduction, collision and post-collision extension, with the rift basin gradually opening after ~785 Ma.