Abstract: The stable carbon isotope (δ¹³C) ratios of whole milk and its isolated components (casein, skim milk, and fat) were determined by elemental analysis-isotoperatio mass spectrometry (EA-IRMS). This technique was found to be repeatable and possess good accuracy with a standard deviation of less than 0.1‰ (n=5). A comparison of the δ¹³C values of different milk samples indicates that the δ¹³C composition is impacted by the type of forage consumed by the cows. The δ¹³C values of milk from farms in which maize is the main roughage are higher than -17.6‰, are relatively lower when the diet contains Leymus chinensis and alfalfa. The δ¹³C values of commercially available milk purchased from different regions demonstrate distinct characteristics, milk samples from China and countries using advanced animal husbandry practices are significant differences. The conclusion of this research verified δ¹³C values in terms of tracing the types of milk and producing areas. The accumulated data was used to lay a theoretical foundation for the application of stable isotope analysis techniques in milk traceability.