Objective:To optimize the preparation technology of human-milk patterned structured triglyceride(HMPST).Methods: Lard was used as a raw material in which the total and Sn-2 position content of palmtic acid are similar to the human milk.Sn-1,3 specific Lipozyme RM IM was the catalyst,lard and free fatty acids react to prepare HMPST.Mono-factor experiment and response surface analysis were used to optimize process parameters.Results: The behavior of the system was explained by the following quadratic equation between sn-2 distribution of palmitic acid and the factors(temperature、reaction time、enzyme load、substrate ratio):Y=-2304.15+63.75A+129.27B+158.19C+45.85D-0.28AB-1.21AC-0.12AD-6.02BC-0.36BD+3.62CD-0.50A2-24.64B2-52.00C2-2.05D2.The optimal conditions were determined as follows: reaction temperature 60.42°C;reaction time 1h;enzyme load 10.15%;substrate ratio(lard∶ free fatty acids)1∶ 2.08.Under these conditions,the total and Sn-2 position content of palmitic acid in HMPST were respectively 20.35% and 71.68% which is very close to that of human-milk.Conclusion:the optimized technology through response surface methodology is suitable for the production of HMPST from lard by interesterification with free fatty acids.The established model between Sn-2 distribution of palmitic acid and the factors is accurate and reliable.