Abstract: A new high selectivity collector DTC which was synthesized by improving xanthate was introduced to the beneficiation tests on a copper-molybdenum tailings ore.At the optimum conditions of grinding fineness -0.074mm 75%,slime 500g/t,Sodium silicate 1000g/t,collector DTC 24g/t,frother 2^# oil 48g/t,the closed-circuit experiments obtained a good results that the Copper molybdenum mixed concentrate 1 contained Cu 18.53%,Mo 4.03%,with recovery of 22.30% for Cu and 45.20% for Mo respectively,and the Copper molybdenum mixed concentrate 2 contained Cu 2.39%,Mo 0.20%,with Cu recovery 3.12% and Mo recovery 4.03% with a process of "raw ore-desliming,grit Cu-Mo part-selective flotation,Cu Mo S bulk flotation followed by Cu Mo-S separation".In addition,the UV-vis spectra and FTIR were also executed to research the mechanism of DTC.The results demonstrated that this new collector which showed a good affinity to Cu²⁺ ions and a powerful collecting ability was a high selectivity collector.