97.2%。 Disaccharides and long chain fatty acids are used as raw materials to directional and controllable synthesize emulsifier, which is one of routes of effectively using low-value agricultural raw materials. Its realization methods include the enzyme method, the physical-assisted method and chemical synthesis method. Sucrose polyester was synthesized with methyl oleate and sucrose. The optimum reaction conditions are: methyl oleate/sucrose=10 (mol/mol); catalyzer is 2.06g; reaction temperature is 138.06℃; reaction time is 5.80h. The product yield reached 97.2%. The result indicated that synthesis of sucrose polyester by two-step method has high-yield.