The invention discloses an ezetimibe eutectic crystal and a preparation method thereof, and particularly relates to an ezetimibe drug-nicotinamide eutectic crystal and a preparation method thereof, belonging to the technical field of drug eutectic crystals. Ezetimibe is used as the drug active component (API), and nicotinamide is used as a eutectic crystal precursor (CCF) to form the ezetimibe-nicotinamide eutectic crystal. The preparation method adopts a solid milling process and comprises the following steps: proportionally adding the ezetimibe and nicotinamide in a ball mill, adding a trace amount of alcohol solvent, and milling. After the ezetimibe-nicotinamide eutectic crystal is subjected to structural characterization through P-XRD, DSC (differential scanning calorimetry), IR and SEM, the eutectic melting point is 106-110 DEG C, and no melting point peaks of API and CCF exist in the eutectic DSC spectrogram. The solubility and dissolution of the ezetimibe eutectic crystal are obviously improved. The method only needs a small amount of solvent, generates fewer byproducts, is simple to operate, can be easily applied in industrial pharmacy, and conforms to the requirements for environmental protection.