The beneficial effects of the synergy between two reagents were realized long time ago. The purpose of using a mixture of collectors is to increase both the recovery and selectivity. In this work, sodium iso-amylxanthate (SIAX) and its isomeride (Y89), having different molecular structures, were used. The separation performance of these collectors were investigated at ratio varies of SIAX and Y89. The results showed that a better recovery of auriferous pyrite was observed with collector mixture comparing to use collector alone. There exist an optimal mass ratio between SIAX and Y89, and it is 1:2. The adsorption measurements of collector mixture and single collector were investigated at pH = 9, indicated that adsorption density of collector on auriferous pyrite surface was improved when collector mixture was used. Infrared spectral analysis suggested stretching vibration peaks from chemical adsorption were increased with using collector mixture. At an optimal mass ratio 1:2 of SIAX:Y89, an Au concentrate assaying 12.79 g/t was produced with an Au recovery of 84.24% from a feed containing only 3.44 g/t Au after one roughing stage. The advantage of this collector mixture can improve the recovery of auriferous pyrite at the same collector consumption, and this collector mixture has great potential for industrial application.