Abstract: Aimed at the problem of stuck and buried pump of pulverized coal during CBM extraction, the 11# coal of Taiyuan Formation of Hancheng block was studied. Using the anionic dispersant SDS, the effects of SDS on the dispersion stability of pulverized coal were investigated by the factors such as particle size of pulverized coal, the amount of dispersant and the concentration. The mechanism between dispersant and pulverized coal was analyzed. The results showed that pulverized coal suspension with different particle sizes has different dispersion effect, with the increasing of particle size, the concentration of SDS pulverized coal suspension decclined in different degrees; Suitable dosage of SDS dispersant and lower concentration of pulverized coal were beneficial to dispersion stability, the mass concentration of dispersant 1.5~2.5 g/L and the mass concentration of pulverized coal less than 30g/L were more suitable for the stable dispersion of pulverized coal; Dispersant changed its viscosity, increased the carrying capacity, meanwhlile viscosity would not affect the flow-back effect of washing liquid in the washing process.