The Chengjiang Formation is one of the most important Neoproterozoic stratigraphic units in South China. Therefore, its accurate depositional age is significant for establishing and completing the Neoproterozoic regional stratigraphic framework of South China. The tuff interbed from the topmost part of the strato-type section of the Chengjiang Formation in Central Yunnan was dated by SHRIMP zircon U-Pb dating. Combined with related research data, it is proved that the Chengjiang Formation is equivalent to the Kaijianqiao Formation and Liantuo Formation, and all the three formations should correlate with the upper part of the preglacial Banxi Group, rather than the glacial Chang’an Formation.