Aiming at the problem that the parameters of soot and sulfur dioxide emitted from the coal slurry drying system of Yanzishan Mine exceeding the standard, a treatment plan was proposed to upgrade the wet dust collector, and additional equipment such as desulfurization tower and wet electrostatic precipitator were installed at the end of the system, and through the implementation of this plan, the upgrading of the coal slurry drying system was completed, which finally made the concentration of soot and sulfur dioxide emission from the flue gas finally achieved the environmental protection standard.