A mobile phone and a battery-fixing device. The mobile phone comprises a body, a battery, and a positioning device. The body includes a first guiding member. The battery is disposed on the body in a detachable manner, and includes a second guiding member corresponding to the first guiding member. The battery moves in the body by the second guiding member moving along the first guiding member. The positioning device is disposed on the body, and fixes the battery in the body.