Abstract: In order to improve the comprehensive utilization efficiency of refining slag and reduce the stacking of refining slag. In this paper, the refining slag of Handan Iron and Steel Group was used as raw material, and the surface area meter, laser particle size meter and X-ray diffraction are used to characterize the refining slag after grinding.The physical properties of refining slag powder were studied by mortar test and slurry test. The results show that mechanical grinding can effectively reduce the particle size and increase the specific surface area of refining slag, and the basic phase composition of refining slag remains unchanged after grinding; Mechanical grinding has a significant effect on the setting time, standard consistency value and activity index of refining slag powder; Under the condition of 80 min grinding, the standard consistency value of refining slag is 27.5%, the setting time is 31 min and the 28 d activity index is 84%, which provides experimental basis and theoretical support for the comprehensive utilization of refining slag in the field of building materials.