Abstract: Silver enriched in the zinc slag of someone zinc smelting plant located in Inner Mongolia was up to 190 ~ 260 g/t,the recyclable percent of which almost was 70%.However,the good comprehensive recovering of silver from this slag was so difficult to achieve,because of the particle size of this slag being very fine,the chemical composition being too complex,a certain amount of polyacrylamide being added,and the form of silver contained in the slag being of variety and so on.According to these characteristics,the comparison and optimization researches of pilot test were investigated based on the labor feasible experiment,and finally established the joint flotation process consisted of one rougher,one cleaner,two scavengers,and the separate redressing of middlings together.The comprehensive index for the pilot test of this optimum process was:when the average grade of silver of feeding was 236.0 g/t,the average grade of silver of concentrate was up to 10743.67 g/t,the recovery of silver topped to 62.06%.