Coal gasification slag (CGS) was an industrial solid waste which was produced in the coal gasification process. In order to achieve “zero emission” of the coal gasification technology, it’s urgent to find a way to utilize the CGS. In this study, utilizing the simple microwave treatment technology, Ce-loaded technology and microwave-assisted Ce-loaded technology, successfully produced the adsorbent. Experimental evidences showed has shown that the surface area of CGS was 70.68m2/g,; after microwave treatment the surface area of CGS was increased to 134.52m2/g, after microwave-assisted Ce-loaded the surface area of CGS was 90.63m2/g. The adsorbents also exhibited a desirable capacity for Congo red (CR) removing and the adsorption process was studied by changing different adsorption conditions. The CR adsorption experiment on the CGS, microwave treatment CGS (MW-CGS), microwave-assisted Ce-loaded CGS (MW-CGS-Ce) showed a maximum adsorption capacity of 55.97mg/g, 86.67mg/g and 353.56mg/g, respectively.