The interfacial interaction between quartz and flotation reagents, such as dodecylammonium (DDA), dodecylalcohol, and their mixture, was investigated by molecular dynamics (MD) simulation. The morphologies of adsorbed surfactant aggregates and water atomic density profiles were obtained, suggesting that DDA can adsorb on the quartz surface and form rod like hemimicelles, while dodecylalcohol dispersed in water without interaction with quartz surface. Simulation results of the mixture indicate that dodecylalcohol can bind with DDA hemimicelle by the hydrophobic attractions among hydrophobic tails without any change on the micellization of DDA. It is useful for adjusting the zeta potential of minerals and improving the flotation efficiency. Moreover, both of those flotaion reagents cannot adsorb on the hydroxylated quartz surface, and thus are unsuitable for the flotation of quartz at low pH.