The Antarctic krill （Euphausia superba）， a keystone species in the Southern Ocean， exhibits energy storage strategies that directly influence both its reproductive success and regional biogeochemical cycling. To investigate the characteristics of lipid accumulation and its relationship with feeding habits in this species， this present study utilized krill specimens collected from Fishing Area 48 in the Southern Ocean between November 2023 and August 2024. Lipid extraction techniques and fatty acid biomarker analysis were employed to determine the lipid content and fatty acid composition of soma tissue. Principal component analysis and linear mixed-effects model were also applied to examine dietary shifts across different maturation stages and their impact on lipid accumulation. The results revealed significant seasonal variation in soma lipid content， with the highest levels observed in autumn， followed by summer and winter. Ovigerous females exhibited significantly lower lipid content [（185.60±37.72） mg/g] compared to non-ovigerous adults [（230.55±70.96） mg/g]. Non-ovigerous adults had higher levels of saturated fatty acids， whereas ovigerous females showed a marked increase in polyunsaturated fatty acids. Lipid content was positively correlated with diatom-associated fatty acids [C16：1n7 and C20：5n3 （EPA）]， but negatively correlated with C18：1n9c， an indicator of trophic plasticity.This study demonstrates that lipid accumulation in Antarctic krill follows distinct seasonal patterns and is closely linked to dietary composition. These findings provide valuable scientific insights into the ecological adaptation mechanisms of Antarctic krill and contribute to the development of effective resource conservation and management strategies.