Disclosed are an implantable medical device, a preparation method thereof and an implantable medical device preform for the preparation of the implantable medical device. The implantable medical device comprises a metal basal body (21) and a polymer film layer (22) covering the surface of the metal basal body (21) and preventing endothelium growth and covering, and also comprises a transitional body (23), which is located between the metal basal body (21) and the polymer film layer (22) and covers at least part of the surface of the metal basal body (21), wherein the transitional body (23) is connected to the polymer film layer (22) and the metal basal body (21). By arranging the transitional body (23) to be connected to the polymer film layer (22) and the metal basal body (21), the polymer film layer (22) will not easily fall off when being implanted into a human body.
