Abstract: To protect the habitat and germplasm resources of Eriocheir sinensis furtherlly and assess the nutritional relationship of the Yangtze River crabs scientifically. Besides, providing reference for exploitation and utilization. Stable isotope technology was employed to in the analysis of the stable isotopes of Eriocheir sinensis and Chiromantes dehaani in Jingjiang section, Xinkai sand and Langshan sand of Yangtze River. In addition, the research detected the δ13C and δ15N values of Eriocheir sinensis and Chiromantes dehaani. The results are used to figure out the area of trophic niches and the niche widths of two species. As the results revealed, there were significant differences in δ13C between Eriocheir sinensis and Chiromantes dehaani（P<0.05). The range of δ13C signatures in Eriocheir sinensisis greater than those of Chiromantes dehaani, indicating that Eriocheir sinensis feeds on more food resources. The range of δ13C signatures in Eriocheir sinensis and Chiromantes dehaani are relatively concentrated at -25.00‰ to -23.00‰ and -26.00‰ to -24.00‰ respectively, which indicate that both species prefer certain food. There is an overlap of trophic niches between Eriocheir sinensis and Chiromantes dehaani indicating the intercomposition for the two species. The overlap of trophic niches in Jingjiang section is larger, which shows that the intercomposition between the two species in Jingjiang section is the most intense. The amplitude of δ13C signatures(CR), δ15N signatures (NR) and total trophic area(Ta) in Eriocheir sinensis are all greater than those of Chiromantes dehaani, which specifies that Eriocheir sinensis has more competitive power for food resources.