The invention provides a medicine sustained-release diaphragm and a preparation method thereof. SF and SA are used as materials, and GA and Gly are added, wherein the concentration of silk fibroin is 1 to 4 percent (mass-volume percent), the content of the SA is 40 to 50 percent of the mass of fibroin, the addition amount of the GA is 1 to 8 percent of total volume, and the addition amount of 75 percent Gly is 1.25 to 2.0 percent of the total volume. Sustained-release dressing obtained in the invention is a diaphragm with uniform thickness, and the thickness is about 0.18mm; the medicine sustained-release diaphragm has a controlled sustained-release effect; in addition, a medicine release mechanism belongs to a Fickian model mechanism. The sustained-release diaphragm prepared with the preparation method provided by the invention has excellent biomechanical properties, moisture absorbing and retaining properties and the like. The sustained-release diaphragm provided by the invention has the advantages of perfect sustained-release model, comfortableness, tensile strength and moisture absorbing and retaining properties, and can respectively meet requirements of a comfortable sustained-release diaphragm, a moisture and retaining sustained-release diaphragm and a comfortable moisture and retaining sustained-release diaphragm; the geometrical size of the medicine sustained-release diaphragm can be changed according to clinical demands.