Allyl aliphatic carboxylates were synthesized by azotropic reaction with benzene between allyl alcohol and capric acid, lauric acid, myristic acid, palmitic acid or stearic acid respectively. allyl aliphatic carboxylates oligomers were prepared from polymerization giving allyl aliphatic carvboxylates in the presence of potassium persulfate in methanol, and the α-sulfonation of these five allyl aliphatic carboxylates oligomers were carried by direct addition of dry sulfur trioxide. Especially, molecular weights of fatty acid alylester oligomers and their sodium salts of α-sulfo fatty acid allylester oligomers were measured by boiling point method.