The invention relates to a method for separating tall oil. The method comprises the steps of thin film distillation, first-stage molecular distillation, second-stage molecular distillation, saponification and esterification, washing and the like. By adopting the method disclosed by the invention, tall oil fatty acid, refined phytosterol and tall oil rosin are obtained by separating the tall oil, wherein the fatty acid content of tall oil fatty acid is more than 90%, and the recovery rate of tall oil fatty acid reaches more than 90%; the phytosterol content of refined phytosterol is more than 90%, and the recovery rate of refined phytosterol reaches more than 80%.