The invention belongs to the technical field of automobiles, and particularly relates to a device for fixing and monitoring a vehicle-mounted mobile phone. The device comprises a storage box body withthe open front end, and further comprises a clamping plate, a return torsion spring and a micro switch which is electrically connected with a vehicle-mounted computer and used for monitoring taking and placing conditions of the mobile phone. The clamping plate is hinged to the storage box body, the rear end of the clamping plate penetrates out from the storage box body, the front end of the clamping plate is located in the storage box body and matched with the top wall of the storage box body to clamp and fix the mobile phone, the two ends of the return torsion spring are fixedly connected with the storage box body and the rear end of the clamping plate respectively, and the micro switch is fixedly installed on a top plate of an instrument and provided with a driving rod sensing the position where the rear end of the clamping plate is located. With the device, the mobile phone can be firmly clamped and fixed inside a vehicle-mounted storage box so as to be conveniently observed and operation, does not occupy external space of the storage box, and can be charged through vehicle-mounted equipment; meanwhile, in cooperation with the vehicle-mounted computer, the device can remind anowner to take back the mobile phone before the owner leaves from a vehicle, and therefore the mobile phone can be prevented from being forgotten in the vehicle.