Based on the survey data of swordtip squid (Uroteuthis edulis) collected by trawlers off the northern East China Sea from 2017 to 2020, we analyzed the biological characteristics of U.edulis, and studied the relationship between the growth characteristics of U. edulis and the environment by using generalized additive models (GAM). The results showed that during the four-year sampling period, the dominant dorsal mantle length and body weight groups of the U. edulis were 80-160mm and 10-170g for females respectively, with no significant differences (P>0.05); while the figures were 60-180mm and 10-170g for males respectively, with significant differences among years (P<0.01). Covariance analysis showed that there were significant differences in body weight-dorsal mantle length relationship in 2017 and 2020 (P<0.05), but no significant differences in 2018 and 2019 (P>0.05). The GAM showed that the M₉ model, in which dorsal mantle length interacted with sea temperature at 25m depth and year and seasonal factors were introduced, was the optimal model. Overall, males were more susceptible than females to external environmental influences on growth. The year has a greater impact on males, while the sea temperature at 25m depth has a greater impact on females. These results indicate that the growth of squid is closely related to environmental variation, with sea temperature being an important influence factor; and males have a more pronounced group of both sizes than females at 160mm dorsal mantle length, as a result of environmental variation and individual survival mechanisms. The biological characteristics of the squid and the influence of the environment on the squid will facilitate the management and conservation of fishery resources and provide a basis for the assessment of fishery resources.