In order to achieve the dual purposes of “solid waste recycling” and “carbon peaking and carbon neutrality”, based on the situation that China's slag reserves are large, the utilization rate is low, and the environmental impact caused by stacking is serious, the slag modification and carbon fixation have become urgent problems to be solved. The research shows that f-CaO in slag swells with water, which makes the stability of slag worse and becomes the main factor affecting the comprehensive utilization of slag. In addition, the tapping temperature of slag can reach above 1500 ℃, and the natural loss of this part of heat is a waste of resources. On the basis of “treating waste with waste and recycling”, high-temperature waste slag can be quenched with high-pressure waste gas (CO₂), which can realize carbon fixation and recycling of resources. By analyzing the present situation of slag modification and the research progress of carbon fixation at home and abroad, a reference for the feasibility of coupling gas quenching technology with hot slag carbon fixation technology and realizing “solid waste recycling” can be provided. Combined with the existing research data of slag, the main chemical components of slag are fitted, and a mathematical model is established to improve the modification efficiency of slag with different chemical components.