The age and tectonic setting of extensive Neoproterozoic volcanic activities around the margin of Yangtze Block were of great significance for reconstructing the position of South China Block in the Rodinia supercontinent. At present, only a few precise ages were obtained from the volcaniclastics of Suxiong Formation in the western margin of Yangtze Block. Therefore, a dacite sample for the stratoype section was collected from Suxiong Formation, with the purpose of determinating the highprecise age in western Sichuan province.Methods:The zircon SHRIMP UPb analysis was used to determinate the age of the dacite sample from the Suxiong Formation, which was carried out by SHRIMP Ⅱ in Beijing SHRIMP Center, Chinese Academy of Geological Sciences.Results:Two precise ages of 838 ± 9 Ma and 780 ± 12 Ma were obtained.Conclusions:Among them, the younger one, 780 ± 12 Ma, was interpreted as the eruption age of the dacite sample, which could represented the tectonic—magma event of the Kangdian rift basin during the period of strong extension, and the older one, 838 ± 9 Ma, represented the tectonic—magma event before the opening of the Kangdian rift basin. Through the comprehensive analysis, the Suxiong Formation was regarded as the product of episodic magmatic activity, locating at the accommodation zones of the Kangdian half graben. Consequently, a series of rift basins, which were related to the mantle plume that led to the breakup of Rodinia supercontinent, should be developed around the margin of Yangtze Block, while the South China Block could be a member of Rodinia supercontinent breakup, through the analysis of volcanic activities and sedimentary records.