Abstract: Oleic acid was compounded and modified by utilizing different emulsifiers in order to enhance its flotation performance at a low temperature.The feldspar ore from Liaoning was taken as the experimental samples to explore the separation condition of feldspar and calcite at a low temperature,and to discuss the action mechanism between modified oleic acid and calcite in flotation.The results showed that modified oleic acid effectively improved the quality of feldspar concentrate by flotation at a low temperature,and the content of CaO of the concentrate was under 0.3% and the removal rate was 85.67%.The tests of zeta potential and FT-IR demonstrated that modified oleic acid adsorption on the surface of calcite was higher than that of feldspar,and the type of adsorption was chemisorption.