The invention discloses a hanfangchin a nanoemulsion injection and a preparation method thereof, containing the hanfangchin a, surfactant, cosurfactant, oil phase and water phase. The nanoemulsion of the invention has the advantages of simple preparation method, transparent appearance, 10-100nm of particle diameter and good stability, thereby remarkably improving solubility of the hanfangchin a, so as to improve bioavailability of drugs, and changing intracorporal process of drugs, so as to increase targeting to liver, reduce toxic and side effect and improve treatment effect.