A mobile phone and a key detection device are disclosed. The mobile phone comprises at least two keys, a baseband chip, a resistor and at least two switch elements. The baseband chip comprises at least two first ports, at least two second ports and an interrupt port. Each first port outputs a first level signal and is correspondingly connected with one end of one key; each second port outputs a second level signal and is correspondingly connected with the other end of the key. One end of the resistor is connected with the interrupt port, and the other end of the resistor is connected with a reference level. One end of each switch element is connected between one first port and the one first port's corresponding key, and the other end of each switch element is connected between the interrupt port and the resistor.