In order to further understand the characteristics of the life history of the Sepia esculenta population in the coastal waters of Jiangsu， the feeding ecology and nutritional niche of the Sepia esculenta were studied by using the carbon and nitrogen stable isotope analysis method based on the samples collected in the coastal ports of Jiangsu. The results showed that there was no significant difference in δ¹³C and δ¹⁵N values between male and female populations of Sepia esculenta； There was a significant correlation between them； the nutritional niche width of male Sepia esculenta （SEAc=0.57‰²） was not significantly different from that of females （SEAc=0.63‰²）， and females were slightly larger than males， and both are highly overlapping （0.62）. Isotopic cluster analysis showed that Sepia esculenta individuals could be divided into three mantle length groups of 75-114 mm， 115-184 mm and 185-204 mm； The niche width of the 114 mm mantle length group was the smallest （SEAc=0.39‰²）； only the niche overlap rate between the 75-114 mm and 115-184 mm mantle length groups was moderate （0.34）， and the niche overlap rate among the other mantle length groups was low. According to the analysis， the change of δ¹³C value of Sepia esculenta was mainly affected by the isotope baseline value and the migration pattern of Sepia esculenta， while the change of δ¹⁵N value was mainly affected by the feeding effect of Sepia esculenta； the height of food resources and habitat utilization between female and male golden squid groups were highly similar； Sepia esculenta at different developmental stages had obvious differences in nutritional niche.