The present invention relates to the technical field of β-sitosterol drugs and provides a drug sustained release agent based on β-sitosterol and a preparation method thereof. The drug sustained release agent based on the β-sitosterol is applied to drugs with the β-sitosterol as a main drug component and is prepared from the components including a drug carrier, a hydrophilic gel material, a erodible matrix material and an insoluble matrix material, wherein the drug carrier is a β-cyclodextrin-polyamide-amine dendrimer composites, β-sitosterol is from a plant raw material, and a host-guest inclusion complex is composed of the main drug component and the drug carrier according to the mass ratio of 0.1:0.1-0.1:5. A preparation method comprises the following steps: preparing the inclusion complex, mixing auxiliaries, carrying out compression moulding and the like. The drug sustained release agent based on β-sitosterol has the characteristics of stable drug concentration, high biological activity, good drug solubility and long acting effect.
