Abstract: A battery replacement apparatus comprises a phone body with at least an open slide seat and a battery with at least a slider. By the slider, the battery can attach to the phone body and slide in a certain direction on the phone body. When there is a need for replace a spare battery, the user shift outward but not take out a running low battery located on the open slide seat of the phone body. Then attach a spare battery into the open slide seat of the phone body by the slider. Next, move the spare battery with a certain direction to the phone body until the running low battery out of the phone body and the spare battery is locked. The apparatus can let a user to replace a battery without turning off the mobile phone.