The sodium fatty acids were firstly prepared by fatty acids with different iodine values which were from surfactant extraction using soybean oil fatty acid as raw material in this study. Effects of iodine value of sodium fatty acids on the flotation of collophanite were then investigated by flotation tests, contact angle measurements, adsorption tests, Krafft point measurements, foaming ability tests, and the resistance to the hard water measurements. Results show that the final flotation recovery was directly proportional to the iodine value of sodium fatty acid. Sodium fatty acid with higher iodine value has higher solubility and dispersity in the solutions, and stronger foaming ability and resistance to hard water. After interacting with collophanite, sodium fatty acid with higher iodine value made the mineral more hydrophobic, thus contributing to better flotation performances.