The invention relates to a preparation method of ultrasound-targeted microbubbles carrying simvastatin, which comprises dissolving simvastatin in tetrahydrofuran and diluting physiological saline to a concentration of 0.01-0.1 mg / mL; adding trimethyl chitosan, Sodium tripolyphosphate, then, compounded into a stable space network, obtained a suspension, freeze-dried and redissolved, transferred the obtained liquid to a vial filled with C3F8 gas, and vibrated the vial with a mechanical oscillator to form a 0.05 mg / mL simvastatin microbubbles, fill the remaining space of the vial with high-pressure C3F8 gas and seal it up, and refrigerate it for later use; inject simvastatin microbubbles into the knee joint cavity and apply ultrasound at the same time, control the ultrasound intensity and time, and target to induce microbubble rupture to reach the maximum ratio. The administration is highly targeted, the medication cycle is shortened, the side effects of long-term medication are reduced, and the dosage of the medication is reduced.