The utility model discloses a coptis-coated insulin granule, which is characterized in that the outer layer of an insulin granule (1) with the length of 20 to 40 nanometers is provided with a coating layer of mixed micro powder of coptis and liquorice with the thickness of 80 to 100 nanometers and the length of 40 to 60 nanometers. The utility model not only can be used as the protective layer with the coptis and liquorice for the insulin, but also can be used as the auxiliary Chinese medicine for the treatment of diabetes. The coptis-coated insulin granule can be made into the medicinal powder, the powder preparation, and also the orally taken medicine as the filled capsule, dispersed liquid and the like, and has the positive explorative effect and practical significance for the diabetes treatment with the orally taken insulin in combination with the Chinese medicine.