Phytosterols have received an extensive attention owing to their excellent cholesterol-lowering activity and the role in cardiovascular diseases prevention. Phytosterol diacid monoesters， the important intermediates in the structural modification of free phytosterols， were often obtained by chemical method with catalyst. The aim of this research was to provide a synthesis technology of phytosterol adipate monoesters and explore the possible mechanism on reducing cholesterol level in vitro. β-Sitosterol vinyl adipate was hydrolyzed to β-sitosterol adipate monester in the presence of Lipozyme TL IM and tert-butanol， and the maximum hydrolysis rate was more than 99%. Compared with free β-sitosterol， β-sitosterol adipate monester possessed lower crystallinity and improved wetting properties. The contact angle was decreased from 131.4° to 98.6°. That was beneficial to dissolve in model cholesterol mixed micelles and swell micellar hydrophobic core. The microstructure of micellar and precipitation phase was observed and found further that β-sitosterol adipate monester kept the cholesterol-lowering activity in vitro due to its precipitation effect on model mixed micelles. This study has certain social value and practical significance to develop phytosterol dietary nutritional supplement.