Abstract: Coal seam water injection technology is one of the important means to prevent and control many mine disasters such as rock burst, dust and fire. The process of coal seam water injection can be summarized into seepage stage, seepage and wetting coordination stage and wetting stage. According to the seepage stage of coal seam water injection, using the triaxial seepage experiment device, based on Darcy’s Law, the surface tension of different surfactant solutions (sodium dodecy sulfate and composite surfactants) and its influence on seepage characteristics of fractured coal are studied in this paper. The variation characteristics of permeability coefficient of different surfactant solutions in coal are compared and analyzed, and the influence of compound surfactant on water injection of fractured coal and the wetting synergistic effect of different surfactants on fractured coal are discussed. The experimental results of thesodium dodecyl sulfate can reduce the liquid surface tension, increase the seepage coefficient from 3.73×10⁻⁴ to 5.6×10⁻⁴, and promote the effect of coal seam water injection wetting. The adsorption between sodium dodecyl sulfate and the coal body increases the tension of the seepage solution on the surface of the coal body crack, decreases the effect of water injection wetting, and finally hinders the seepage wetting process. By adding other raw materials to configure a new composite surfactant, it can effectively reduce the adsorption, enhance the seepage effect and improve the water injection efficiency. The conclusions obtained can provide reference for raw material optimization and parameter setting of on-site coal seam water injection, and provide new ideas for the research of coal seam water injection technology.