A medical instrument and a manufacturing method thereof are provided. The medical instrument includes a biomedical metal layer and a polymer film. The polymer film is a biodegradable polymer material. The manufacturing method includes the following steps: providing the biomedical metal layer, immersing the biomedical metal layer in a polymer solution, performing a baking process on the biomedical metal layer coated with a polymer film, forming the biomedical metal layer coated with the polymer film, taking out the biomedical metal layer coated with the polymer film to fabricate the medical instrument. The biodegradable polymer film and the biomedical metal layer are combined into the medical instrument, so that a physician performs a surgery more easily. In addition, decomposition time of the polymer film can be preset, so as to achieve efficacy of blocking soft tissue cells having a higher growth rate.