The investigation of the behavior of CO2 absorption into the low Al2O3 electric arc furnace (EAF) oxidizing slag under wet grinding was investigated in this paper. The slag was wet ground in the vibration ball mill in the presence of CO2 at room temperature. The observation of the CO2 absorption was made with constant pressure method. The CO2 absorption increased steeply in the early stage of grinding. It occurred simultaneously with the grinding and immediately ceased when the grinding was stopped. The CO2 absorption occurred at the interface between the slag and the water which was saturated with CO2. The CO2 absorption increased as the finer particles were formed by the grinding process, and as the interface between slag and water was increased by the vibration process. A large amount of CO2 absorption and high conversion ratio was observed in the oxidizing slag with low Al2O3 in comparison with those of the slag with the high Al2O3 content.