Stable isotopes have been used in many research areas as natural labels, and are becoming the more appropriate option for the aquatic ecological studies. An organism’s stable isotope ratios (δ¹⁵N and δ¹³C etc) are an integration of the isotopic signatures of preys that have been assimilated through time, the organism will come into isotopic equilibrium with its diets depending on growth and tissue turnover rates, and the ratios can change with different food, are good labels of organism living conditions. According to the carbon stable isotope ratio of organisms from Changjian Estuary and adjacent Southern Yellow Sea in spring, we calculated their feeding habits. It is found that, (1) the feeding habits of some organisms calculated with stable isotope method or stomach analysis method in Changjians Estuary and Southern Yellow Sea were different, we could speculate that the energy sources of the two areas were different or some organisms could change with the habits, change their food sources with time and areas; (2) if the feeding habit types of stomach isotope analysis method was the same to that of stable isotope technique, only three organisms had different feeding habits in twentyfour common organisms, which showed the table isotope technique could be used to calculate the feeding habit of organism, and it had many advantages in calculating feeding habits of organism in different areas or time.