In this study, a modified starch was utilized to selectively separate barite from fluorite.The results of flotation tests showed that a highly selective separation of fluorite from barite was obtained when 250 mg•L-1 of modified starch and 13.16×10−5 mol•L-1 sodium oleate was used in neutral solutions. FTIR spectra results showed that the modified starch can adsorb on the fluorite and barite surfaces. Zeta potential analyses indicated that the modified starch has little effect on the adsorption of sodium oleate on the fluorite surface, although it interferes with the adsorption of sodium oleate on the barite surface. Contact angle measurements results corresponded well with the flotation results.