A mobile phone and a method for automatically switching between incoming call alert modes of the mobile phone are provided. The mobile phone comprises a body, a control unit, a receiver and a sensor. The control unit disposed in the body includes an incoming call alert control module providing several incoming call alert modes. The receiver and the sensor are electrically connected to the control unit. The receiver suitable for receiving an incoming call signal transmits the incoming call signal to the control unit. The sensor suitable for sensing an included angle between a lengthwise axis of the mobile phone and a level transmits a signal comprising the data of the included angle to the control unit. When the control unit receives the signal of the detected included angle, the incoming call alert control module enters one of the incoming call alert modes according to the detected included angle.