In South China, the Ediacaran Doushantuo phosphorites in Weng’an, Guizhou Province provide great implications for our understanding of early animal evolution because of the three-dimensional preserved embryos of the phosphorite deposits, which probably represent the oldest fossil evidence for multicellular animal life on earth. Phosphorus is a limiting nutrient in controlling primary productivity which can place constrains on oxygen concentrations. Therefore, the Doushantuo phosphorite may shed light on the possible linkage between oxygen and the emergence of early animals. However, it is ambiguous if stable carbon and oxygen isotopes of sedimentary phosphates can preserve primary isotopic signals. Here, I present high-resolution C-isotope data of the Doushantuo carbonates and phosphorites as well as the underlying tillite of the Nantuo Formation from two sections near Weng’an. For the Datang section, all of the Nantuo tillite samples have negative δ¹³C_carb values ranging from -2.1‰ to -16.8‰and negative δ¹⁸O values ranging from -7.1‰ to -27.2‰. All of the phosphorite samples have negative δ¹³C_carb values ranging from -1.4‰ to -4.0‰, with δ¹⁸O values ranging from -4.3‰ to -10.1‰. For the lower phosphorites at Chuanyuandong section, δ¹³C_carb values vary between -1.8 and -6.4‰and the δ¹⁸O values range from -4.9‰ to -14.8‰. For the upper phosphorites, the δ¹³C_carb values range from -0.9‰ to 1.7‰, and the δ¹⁸O values from -0.2‰ to -4.5‰. For the Nantuo tillite, the striking negative δ¹³C_carb and δ¹⁸O values as well as clear covariance between δ¹³C_carb and δ¹⁸O suggest that nearly all of the primary C and O-isotopic compositions have been reset by meteoric diagenesis. The correlative lower phosphorite deposits show clear covariance between δ¹³C_carb and δ¹⁸O though the Chuanyuandong phosphorites show more negative values than the Datang section, which means the alteration of the δ¹³C_carb and δ¹⁸O signals by meteoric diagenesis at Chuanyuandong is more significant than at Datang. In contrast, the upper phosphorites characterized by the more positive δ¹³C_carb and δ¹⁸O values as well as a lack of covariance between δ¹³C_carb and δ¹⁸O may have recorded the primary isotopic signals of seawater from which the phosphorites were formed. In conclusion, it appears that the chemical composition of phosphate-rich seawater may have changed during the two episodes of phosphogenic event of the Doushantuo Formation. Moreover, caution is needed when similar geochemical data are used for paleoenvironmental reconstruction.