[Aim]  This study aimed to systematically investigate the effects of bidirectional temperature stress on the antioxidant and detoxification enzyme activities of Tuta absoluta larvae and their dynamic response mechanisms. [Methods]  Various temperature gradients (-10, -5, 0, 26, 35, 37.5, 40 °C) and exposure durations (0.5, 1, 2 h) were simulated to measure the activity changes of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), total antioxidant capacity (T-AOC), glutathione S-transferase (GST), multifunctional oxidase (MFO), and carboxylesterase (CarE). Correlation analysis was performed to reveal their coordinated regulatory mechanisms. [Results]  Short-term exposure to extreme low temperatures significantly activated SOD, POD, and CAT activities, whereas prolonged exposure led to a marked decline. In contrast, high temperatures initially inhibited CAT and MFO activities, but GST activity surged after 2 hours, indicating that temperature fluctuations have distinct time-dependent regulatory effects on enzyme activity. SOD, POD, and CAT exhibited a strong positive correlation with T-AOC, forming a chain-like antioxidant network. GST showed a significant negative correlation with MFO, maintaining detoxification function via metabolic shunting under high-temperature conditions. The critical threshold temperature for functional imbalance was identified as 37.5 °C, which significantly increased T-AOC but suppressed MFO activity. Moreover, short-term exposure to 0 °C specifically activated CarE, suggesting an adaptive response to host plant ester toxins. [Conclusion]  This study is the first to reveal the "acute compensation-metabolic shunting-critical threshold" dynamic response pattern of T. absoluta larvae under bidirectional temperature stress, providing a theoretical foundation for the integrated management of invasive pest species worldwide.