Abstract: The molybdenum grade is 0.21% and the lead grade is 0.0049% in a low grade disseminated molybdenite ore in Qinghai Province. Process mineralogy research and beneficiability condition test were carried out for the low grade molybdenum ore. Diesel oil was used as collector and sodium silicate was used as regulator. After flotation process of one stage roughing, five stages cleaning and two stages scavenging, the Pb content of molybdenum concentrate obtained was 0.98%. The sale price of molybdenum mines was affected due to exceed standards lead levels. In order to reduce the lead content of the molybdenum concentrate, the process of regrinding and detoxification combined with the addition of phosphoknox, an inhibitor of inhibiting lead, was adopted for the molybdenum concentrate containing excessive lead. Finally, the lead content of molybdenum concentrate was reduced from 0.98% to 0.074%, molybdenum grade is increased from 0.21% to 53.95%, molybdenum recovery reached 90.18%, realizing effective recovery of molybdenum.