Abstract: In order to explore the influence of pulp potential on flotation of copper molybdenum ore, chalcopyrite and molybdenite were used as samples to study the effects of pulp pH, flotation reagent type and consumption on pulp potential. The results show that the optimum slurry potential is 360 mV and pH is 8. When sodium sulfide, ammonium sulfate and sodium carbonate are mixed in 1:1:1, chalcopyrite is easier to reach the floating potential range. At the same time, when the pulp pH is about 9, mercaptoacetic acid can well inhibit the flotation of chalcopyrite, and has a good selective effect on molybdenite, which is conducive to the separation of the two. In the mechanism analysis, it is pointed out that the main reason for the flotation of chalcopyrite is the formation of a large amount of CuS in the pulp at pH 8.