Pressure filtration has always been a time-consuming process in coal mine production. Because fine particles will block the tiny holes in the filter cake and make it difficult for the water in the filter cake to flow out, the efficiency of the pressure filtration process often determines the efficiency of the whole flotation. How to improve the processing capacity of the pressure filtration process has become one of the major problems in the coal washing process. This paper mainly discusses the influence of new filter aid on the sedimentation of coal slime in multi-source water. Through research, it is found that the new flocculant can effectively promote the sedimentation and filtration efficiency of coal slime. Among them, Ca 2+ and PAMAM improve the dewatering of coal slime through chemical reaction and physical adsorption respectively. The experiment shows that the dosage of filter aid is the best when the conductivity is above 6.5, and the dosage of flotation agent can be reduced, which has a positive impact on the coal flotation process in the laboratory environment. The new filter aid has broad prospects and will be gradually optimized and improved in the promotion practice.