Provided is a method for modifying extracellular vesicles, the method comprising : isolating and purifying extracellular vesicles; then sequentially connecting a membrane insertion group, a linking group and a targeting ligand; assembling the connected membrane insertion group-linking group-targeting ligand on the surface of the purified extracellular vesicles; and after incubation for a period of time, removing the free membrane insertion group, linking group and targeting ligand, so as to obtain high-purity extracellular vesicles modified with ligands. The modified extracellular vesicles can recognize and bind to a specific receptor on the diseased cell membrane by a targeting module, and perform targeted delivery of a drug into cells, which can be widely used in the fields of treatment drugs and diagnosis of diseases.