The invention discloses a vascular stent coating with a drug sustained-release function, which is prepared from the following raw materials: polycaprolactone, chitosan, collagen, medicine, nano magnesium, nano titanium dioxide, dendrobium polysaccharide, tea polyphenol, dopamine, gelatin, nano zirconia, hirudin, and ethanol. The invention also discloses a preparation method of the vascular stent coating with the drug sustained-release function. The binding strength of the vascular stent coating and a substrate is 4.8 to 5.9 MPa, the binding strength of the vascular stent coating and the stent substrate is high, the degradation time of the vascular stent coating is 68 to 86 days, the vascular stent coating can be completely degraded after 90 days, the large-area shedding and swelling phenomena do not occur in the degradation process, the stability and biocompatibility are good, no cell toxicity, coagulation and thrombosis are formed, and no inflammatory response is generated.