In this paper, the effect of various inhibitors, such as disodium hydrogen phosphate, citric acid and sodium silicate, on flotation separation performance of powder quartz and andalusite was investigated by using sodium oleate as the flotation collector. The results showed that disodium hydrogen phosphate was an efficient inhibitor for separating andalusite from powder quartz. When the concentration of disodium hydrogen phosphate was set to the optimum one of 0.47×10^-2 mol/L and the pH of flotation liquid to 8.5, the recovery difference between andalusite and powder quartz was as high as 47.86%. The results of infrared spectra and Zeta potential analyses revealed that the interaction between sodium oleate and andalusite powder resulted from the physical and chemical adsorption, while that between sodium oleate and powder quartz was due to the physical adsorption, suggesting that sodium oleate was more efficient in collecting andalusite. Also disodium hydrogen phosphate was found to play the role of desorption of powder quartz from sodium oleate, consequently inhibiting the flotation of powder quartz and resulting in the flotation separation of powder quartz from andalusite.