Abstract: To clarify the physiological responses, histological damage, and molecular mechanisms of large yellow croaker (Larimichthys crocea) under acute low-temperature stress, healthy juveniles with an average body weight of (53.14±0.76) g were used as experimental material. The median lethal temperatures (LT₅₀) were first determined as 5.768℃ at 24h and 6.774℃ at 48h, respectively, indicating that 8℃ represents a critical sublethal low temperature for this species. Based on the determined LT₅₀ values, four temperature gradients were established, including 20℃ (control), 16℃ (moderate low), 12℃ (low), and 8℃ (extremely low), and fish were exposed for 24h and 48h, during which hepatic histological structure, activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA) content, and mRNA expression levels of antioxidant, lipid metabolism, and inflammation-related genes were systematically measured. The results showed that the activities of GSH-Px and CAT were generally inhibited under low-temperature stress, although transient induction occurred at moderate low temperatures. SOD activity increased with decreasing temperature and showed significant temporal differences under different low-temperature treatments. MDA contents in the 12℃ and 8℃ groups were significantly higher than those in the control and 16℃ groups (P<0.05), whereas the MDA content at 48h was significantly lower than that at 24h under the same temperature (P<0.05). Histopathological observations revealed that hepatic injury was aggravated with decreasing temperature and was mainly characterized by hepatocellular vacuolation and ballooning degeneration. Damage showed no obvious aggravation over time at 16℃ and 12℃, whereas ballooning degeneration continued to worsen at 8℃. The expression of antioxidant genes (Cu/Zn-SOD, Mn-SOD, GSH-Px, CAT) and lipid metabolism genes (SCD-1a/b, FAS) was significantly up-regulated at 16℃ and 12℃ (P<0.05), but suppressed at 8℃ with no significant difference compared to the control. The inflammatory genes (IL-1β, TNF) were significantly up-regulated only at 16℃ (P<0.05). Transcriptome analysis showed that low temperature significantly induced differential expression of genes related to oxidative stress, apoptosis, and lipid metabolism remodeling. Cluster heatmap and Pearson correlation analysis verified significant co-expression relationships among these pathways. In conclusion, large yellow croaker exhibits an obvious threshold effect in low-temperature tolerance: at 8℃, a temperature close to the LT₅₀, the antioxidant system becomes imbalanced, liver tissue sustains irreversibly injured, and key defensive genes are transcriptionally inhibited, jointly leading to collapse of physiological homeostasis. This study reveals the physiological and molecular basis of low-temperature-induced mortality in L. crocea, and provides a scientific basis for overwintering management and the development of anti-stress strategies in aquaculture.