Abstract: Surface tension tests, quantum chemical computation and flotation tests were carried on the self-synthesized Diester Gemini quaternary ammonium salt. The results indicated that Diester Gemini quaternary ammonium salt has lower CMC, stronger cationic, larger molecular electro negativity, and at the low concentration of 5×10^-6 mol/L, resulting in quartz recovery at 88.89%, fluorapatite recovery at 4.04%. According to the results of contact angle tests and molecular dynamics simulations, Diester Gemini quaternary ammonium salt prefer to adsorb on quartz surface than fluorapatite. Thus, the Diester Gemini quaternary ammonium salt can be used as a cationic collector for quartz from fluorapatite.