N,N-bis(dodecylamidoethyl)-N-propyl sulfonate having two alkyl amide chains was prepared using an excess of 1,3-propane sultone and intermediate N,N-bis(dodecylamidoethyl)-amine, which was synthesized by amidation from lauric acid and diethylenetriamine, in toluene/acetone mixed solvent under reflux conditions. The chemical structures of intermediate and this surfactant were characterized by FT-IR, ESI-MS, and 1HNMR methods. The krafft point of this surfactant is 37.3℃ by electrical conductivity method. Its surface tension in aqueous solutions was determined by pendant drop method to study the adsorption behavior at the water/air interface. The values of CMC，γCMC，C20，Γ∞，ΠCMC, Amin were obtained by the γ-lgC curves, with 6.40×10-4 mol/L critical micelle concentration(CMC), and 37.33 mN/m the lowest surface tension (γCMC) at 45℃. The interfacial tensions between different concentration surfactant solutions and n-alkane had been investigated at 45℃ over a wide NaCl dosage range from 0% to 5%. The minimum interfacial tension between 1×10-4mol/L (5% NaCl) surfactant solution and nonane reduced to 3.39×10-3mN/m at 45℃, and at the same time, the salting-out phenomenon does not occur.