The carbon dioxide-water system was used to investigate the flowing gas-liquid metastable state. The experiment was carried out in a constant volume vessel with a horizontal circulation pipe and a peristaltic pump forced CO2 saturated water to flow. The temperature and pressure were recorded. The results showed that some CO2 escaped from the water in the flow process and the pressure increased, indicating that the gas-liquid equilibrium was broken. The amount of escaped CO2 varied with flow speed and reached a limit in a few minutes, entitled dynamic equilibrium. Temperature and liquid movement played the same important role in breaking the phase equilibrium. Under the experimental conditions, the ratio of the excessive carbon dioxide in the gas phase to its thermodynamic equilibrium amount in the liquid could achieve 15%.