Under global climate change， the combined effects of ocean acidification and warming on mercury （Hg） ecotoxicity and their underlying mechanisms have become a research focus in environmental science. This paper has comprehensively reviewed existing studies and analyzed the interactive effects of acidification and warming on Hg bioaccumulation， toxicity effects， and biological responses. The key findings reveal that ocean acidification primarily mitigates Hg toxicity by inhibiting Hg bioaccumulation and inducing energy compensation and stress responses in organisms， demonstrating their antagonistic interaction. In contrast， warming exerts a synergistic effect with Hg pollution， i.e.， exacerbating Hg toxicity by increasing metabolic rates， promoting Hg accumulation， and inducing oxidative damage. Under the more realistic scenario of combined acidification and warming， the inhibitory effect of acidification on Hg accumulation is partially offset， while immune defense downregulation and reproductive damage are intensified， ultimately leading to an overall enhancement of Hg toxicity. These findings suggest that assessments based solely on single climate stressors （acidification or warming） may substantially underestimate the long-term ecological risks of Hg pollution in marine ecosystems. Such underestimation stems from the neglect of warming’s counteraction on acidification and the dual energy demand arising from combined acidification and warming exceeding an organism’s compensatory capacity. Future research should prioritize integrated assessments across multi-stressors， multigenerational exposure， and ecosystem levels to reveal the complex mechanisms of Hg toxicity under global climate change， provide a scientific basis for developing accurate risk management strategies.