The monomyristoyl maltose was synthesized in tertiary butanol with lipase as catalyst.The factors of the reaction,such as the molar ratio of myristic acid to maltose,the dosage of lipase,temperature and time of the esterification,were studied.The product was identified by HPLC.The highest yield was 90%,when choose the conditions as follows:the dosages of maltose and Novozym 435 were 29 mmol/L and 35 g/L,the molar ratio of myristic acid to maltose was 4∶1～6∶1,and the temperature and time were 60 ～70 ℃ and 48～60 h.To remove the unreacted maltose and fatty acid,we selected ethanol and n-hexane,respectively.The purified monoester was tested by HPLC and LC-MS,and was identified it as monomyristoyl maltose.