A mobile phone and a battery-release device. The mobile phone includes a body, a positioning device, and a battery. The positioning device includes a magnet. The positioning device is disposed in the body in a manner such that it moves between a first position and a second position. The battery is disposed in the body in a detachable manner, and includes a moveable engaging member. When the positioning device is in the first position, the engaging member is attracted by the magnet so that the battery is fixed in the body. When the positioning device is in the second position, the engaging member is not attracted by the magnet so that the battery is separated from the body.