A method of delivering drugs to the inner ear facilitated by microbubble, including mixing a microbubble composition and a drug into a microbubble-drug mixture, applying the microbubble-drug mixture to middle ear cavity, and placing a mechanical oscillation wave source in the external ear canal or cranium located behind the ear. The mechanical waves generated by the mechanical oscillation wave source penetrate through the tympanum or cranium and indirectly induce the cavitation with the microbubbles in the middle ear cavity. The permeability of the round window membrane thus increased and facilitated the drug penetrating the inner ear through the round window membrane. Therefore, the mechanical oscillation wave source could be indirectly applied to the microbubbles and induced the cavitation effect in a non-invasive way.