The aim of the present study is to investigate the effects of high CO₂ in the ocean on the physiology of Aristotle's Lantern muscle. After 140-day long-term high CO₂ exposure, the muscle respiration in 3000 μL/L group decreased nearly 40% compared with control group. The ATP content was not significantly influenced by CO₂. Acetylcholinesterase content in high CO₂ groups decreased, but without significance. And the muscle contractile of high CO₂ groups was lower than that of control group. These experiments showed that CO₂ plays an important role in the muscle physiology.