An anti-theft device for a mobile phone consists of a main phone and a sub-phone, wherein, the main phone comprises an anti-theft signal receiving and sending device for the main phone, an electronic lock, a main phone control module, a fingerprint identification module, and a power supply of the main phone; the sub-phone comprises a sub-phone antenna, an anti-theft signal receiving and sending device for the sub-phone, a sub-phone control module, and a power supply of the sub-phone; the anti-theft signal receiving and sending device for the main phone, the electronic lock, the fingerprint identification module, and the power supply of the main phone are connected with the main phone control module through conducting wires; the sub-phone antenna is connected with the anti-theft signal receiving and sending device for the sub-phone through a conducting wire; the anti-theft signal receiving and sending device for the sub-phone and the power supply of the main phone are connected with sub-phone control module through a conducting wire; and the anti-theft signal receiving and sending device for the sub-phone exchanges data with the sub-phone antenna through a wireless signal. The anti-theft device has the following advantages: the device, after being stolen, can not be used normally, so that the safety of the mobile phone can be ensured, and the device has wide market application prospect.