A wearable electronic device includes a main body and a battery module to provide power to the main body. The main body includes a first power contact arranged on a bottom thereof and a first magnet arranged therein. The battery module includes a sealed case, a battery received in the case, a second magnet received in the case, and a second power contact arranged on an upper surface of the case and configured to electrically connect to the battery. When the main body and the battery module are attached to each other through magnetic attractive force between the first magnet and the second magnet, the second power contact is electrically connected to the first power contact.