Argentinean shortfin squid, Illex argentinus, is one of the most important world fishery species characterized by semelparous reproduction, where the reproductive energy accumulation significantly links to the reproductive potential and the survivorship of hatchlings. To better understand the female's reproductive energy accumulation and the responsive relation to their living environments, we randomly sampled squid specimens from southwest Atlantic during 2019 and 2020, and applied the technique of tissue energy density determination to determine the energy density of reproductive tissues, namely ovary, oviducts and nidamental glands, and then to estimate the tissues' energy accumulation. We also applied the generalized additive mixed-effects models (GAMM) to investigate the relationships between reproductive tissues' energy density, energy accumulation and sea surface oceanic variables, namely sea surface temperature (SST) and chlorophyll a concentration (Chl.a). The results indicated that during the period of sexual maturation, the ovary energy density varied significantly, but both oviducts and nidamental glands did not show significant differences in the energy density with sexual maturation. In terms of energy accumulation, all of the three tissues showed an increasing trend till spawning. The energy density of ovary and nidamental glands was found in significant relation to SST, where the ovary energy density increased with increasing SST when SST was higher than 11 ℃, while the nidamental glands density declined with increasing SST. However, it was found that only ovary energy accumulation was significantly correlated with SST, declining with increasing SST. Regarding chlorophyll-a concentration, there were significantly positive correlations between ovary energy density, oviducts energy density and Chl.a, indicating positive effects of primary production on both tissues' energy density. Additionally, there were also significant effects of Chl.a on the energy accumulation of both ovary and nidamental glands. Cumulatively, the female Argentinean shortfin squid accumulated reproductive energy continuously till spawning, and the energy density and energy accumulation of the reproductive tissues were significantly correlated with SST and Chl.a, but the effects on the energy density and energy accumulation from the sea surface oceanic variables were likely to be tissue-specific.