In order to have a deep understanding of the role of ocean squid in Northwest Pacific Ocean food web, samples were collected during the comprehensive scientific survey launched by the Ministry of Agriculture and Rural Affairs in 2021 and 2022.Carbon and nitrogen stable isotope technology was used to analyze the muscle stable isotopes and nutritional niches of two cephalopod species, Ommastrephes bartramii and Onychoteuthis borealijaponicus, in Northwest Pacific Ocean. The results show that O.bartramii δ¹³C and δ¹⁵N values between sites were significantly different. O.borealijaponicus δ¹³C values between the two sites showed significant differences, while the δ¹⁵N values were not significant. Muscle δ¹³C and δ¹⁵N values between O.bartramii and O.borealijaponicus showed significant differences.During ontogeny,the δ¹³C and δ¹⁵N values of O.bartramii and O.borealijaponicus were not significantly associated with carcass length.The nutrient niche width of O.bartramii （SEAc=0.35‰²） is greater than that of O.borealijaponicus （SEAc=0.20‰²）, with a moderate overlap between the two squids （0.314）. The high niche overlap between males and females is 0.988 and 0.76, respectively.The analysis shows that the δ¹³C values of O.bartramii and O.borealijaponicus are influenced by SST and feeding effects, while the δ¹⁵N values are influenced by feeding effects. The utilization of food and habitat resources was highly similar in both female and male cephalopod groups.