This study aim to develop the carbon storage potential of γ-C2S stainless steel slag, and to maximize the comprehensive utilization rate of stainless steel slag. The impacts of several key parameters, such as molding pressure, liquid-solid ratio, CO2 partial pressure on the carbonation performance were studied, and the CO2 storage capacity of stainless steel slag was evaluated, so that a better carbonation process of the stainless steel slag could be offered. The composition and microstructure of the carbide products of stainless steel slag were characterized by XRD, SEM/EDS, DSC/TG to explore the carbonation mechanism. The results show that the optimal carbonation parameters are as follows: liquid-solid ratio 10%, molding pressure of 250 MPa, and CO2 partial pressure of 03 MPa. In above mentioned conditions, about 123.6 g of CO2 is stored in every kilogram of stainless steel slag. The γ-C2S carbonation is main reaction during the carbonation progress. Flake and granular CaCO3 are first observed, and then they gradually grow into clusters over time. Therefore, the storage and preparation of carbonized products using stainless steel slag are practicable.