High-purity extraction method of stem cell exosome

The invention discloses a high-purity extraction method of stem cell exosomes. The high-purity extraction method comprises the following steps: (1) collecting an exosome stock solution; (2) exosome stabilization: mixing the exosome stock solution obtained in the step (1) with PEG (Polyethylene Glycol) to enable the concentration of the PEG to be 1.6-2.5%, and incubating for 1-3 hours to obtain a stable exosome cross-linking system; (3) exosome protection: adding a sucrose solution into the exosome cross-linking system obtained in the step (2) to enable the concentration of sucrose in the system to be 10-15% so as to obtain an exosome ultracentrifugation system; and (4) enrichment and purification: enriching the exosome obtained in the step (3) by one or repeated ultracentrifugation to obtain a purified exosome precipitate. PEG is adopted for crosslinking to form a net, and exosomes are attached to the net; the sucrose solution is added to protect the exosome, so that the exosome is prevented from being damage