In order to realize the efficient utilization of sodium oleate, which is a collector for iron ore flotation, the effect of ethyl oleate on the reverse flotation separation of quartz from fine hematite was investigated by carrying out quartz pure mineral flotation test, binary mixed mineral flotation test and actual mineral flotation closed-circuit test. The promoting effect mechanism of ethyl oleate on the flotation of quartz by sodium oleate was clarified by infrared spectroscopy, surface tension measurement and contact angle measurement. The results show that in the pure mineral flotation test, when the sodium oleate is 160 mg/L and the pulp pH is 11.0, the maximum recovery of quartz increases from 80.34% to 94.85% after adding 40 mg/L ethyl oleate. In the flotation test of binary mixed minerals of quartz and hematite, compared to the dosage of 160 mg/L sodium oleate, when the dosage of sodium oleate is 120 mg/L and the dosage of ethyl oleate is 40 mg/L, the grade of iron concentrate increases from 62.32% to 65.04%, and the recovery of iron concentrate increases from 89.64% to 93.86%. In the actual mineral flotation closed-circuit test, compared with the flotation index under the single sodium oleate system, the grade and recovery of iron concentrate increase by 3.01 percentage points and 3.52 percentage points respectively after adding ethyl oleate. The promotion effect mechanism of ethyl oleate on the flotation of quartz by sodium oleate is that ethyl oleate and sodium oleate are combined by hydrogen bond, which enhances the adsorption strength of sodium oleate on the surface of quartz, strengthens the adsorption stability of the reagent, and improves the hydrophobicity and floatability of the quartz surface.