A biodegradable in vivo supporting device is disclosed. In one embodiment, a coated stent device includes a biodegradable metal alloy scaffold made from a magnesium alloy, iron alloy, zinc alloy, or combination thereof, and the metal scaffold comprises a plurality of metal struts. The metal struts are at least partially covered with a biodegradable polymer coating. A method for making and a method for using a biodegradable in vivo supporting device are also disclosed.