Abstract: To improve the water injection effect of anthracite coal seam, the anthracite sample was modified by soaking with sodium dodecyl sulfate(SDS) of different concentrations, and the surface groups, coal/water dynamic contact angle, natural water absorption and particle size distribution of impact dust production before and after immersion modification were tested and analyzed. The results show that the wettability of anthracite is enhanced by immersion modification of SDS solution, the dynamic contact angle of coal/water decreases exponentially with the increase of SDS solution concentration, and the natural water absorption of modified coal increases exponentially with the increase of SDS solution concentration. The particle size - mass distribution of natural coal samples and modified coal samples under saturated water has fractal characteristics. The higher the natural saturation rate of coal samples, the smaller the fractal dimension of particle size-mass distribution of impact crushing dust. With the increase of SDS solution concentration, the fractal dimension of particle size-mass distribution of impact crushing dust of modified coal samples decreases, that is, the total amount of fine dust produced decreases.