To investigate the energy storage capabilities of species in Northwest Pacific Ocean, this study utilized fish and squid as case study, and the samples were collected by "Songhang" distant water fishery research vessel. The technique of tissue energy density determination was applied to measure the energy density of soma tissue of fish and squid, and the mixed-effects models were used to analyze the effective relationships between soma tissue energy density and marine environmental variables. The results showed that the soma tissue energy density of fish was greater than that of squid, with tissue energy density measured at （23.50±2.80） kJ/g for fish and （19.67±1.16） kJ/g for squid. Among the fish, Ceratoscopelus townsendi had the highest soma tissue energy density, with a mean value of （28.75±0.96） kJ/g, while Hyperoglyphe japonicus had the lowest soma tissue energy density, at （20.37±1.04） kJ/g. Regarding the squids, the highest soma tissue energy density was found in Eucleoteuthis luminosa [（20.07±0.39） kJ/g], and the lowest density was in Onychoteuthis borealijaponicus [（18.42±0.22） kJ/g]. Both fish and squid in higher latitude areas exhibited higher energy density in their soma tissues, which was significantly correlated with the interaction of latitude×longitude. In addition, they had greater soma tissue energy density in areas where the sea surface height was 0 m, and showed an increase trend when the net primary production was larger than 12 mg/（m³·d）. However, their soma tissue energy density decreased with increasing sea surface temperature. This study indicates that there is latitudinal trend in the distribution of soma tissue energy density of fish and squid in Northwest Pacific Ocean, where the sea surface height, sea surface temperature and net primary production have significant effects on the energy accumulation per unit of soma tissue of fish and squid. The study puts forward our understanding of the environmental adaptability of marine species, and warrants future research on the marine ecosystem stability in Northwest Pacific Ocean.