Abstract: To improve the value of monomer acid from dimmer acid byproduct, the compositions of the monomer acid, which are mixed by saturated, unsaturated and isomeric fatty acid compose, are analyzed. Isomeric fatty acid by wraping urea is mixed with monomer acid, oleic acid to form some flotation reagents, which is used in Anshan iron ores flotation tests. The results of open circuit and close circuit shows that, when the temperature is 25℃, the Fe concentration was enriched to a concentration of 66.38%. The Fe concentration in tailing was reduced to only 14.90%. The recovery of Fe is 84.19%. Compared with KS-Ⅱ flotation reagents, it can improve Fe recovery, decrease Fe in tailing and reduce the consumption of collector.