The invention belongs to the technical field of medicines and relates to a myricetin nanosuspension and a preparation method thereof. The myricetin nanosuspension is prepared by adopting a settling method and a high-pressure homogenization method, and the formula comprises myricetin and a stabilizer according to the weight ratio of 1: 0.25-1: 2.5. According to the preparation method provided by the invention, the formula is optimized, Tween-80, Cremophor EL and D-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS) are screened as the stabilizer, the prepared myricetin nanosuspension has stable nature and simple composition of the formula, the preparation process is simple, convenient and feasible, and the particle size range is 100nm-300nm; and by reducing the particle size of a medicament, the solubility and the dissolution of the myricetin are obviously improved, and the oral bioavailability and the in-vivo tissue distribution of the myricetin are further improved. In addition, the myricetin nanosuspension can be freeze-dried, and proper excipients are added into the obtained freeze-dried powder for further preparing oral liquid, tablets, granules, capsules and other different oral preparations so as to facilitate clinical applications.