The invention provides a desktop POS terminal device, which comprises a POS machine main body, an angle adjustment unit and a loading base, wherein the angle adjustment unit comprises a bottom plate,a gear, a motor and a rack; the rack is arranged on the bottom plate; the gear is connected with the driving shaft of the motor; the gear is driven by the motor to rotate; and the gear is engaged withthe rack. The angle of the POS machine is adjusted in real time through the angle adjustment unit, the structure is simple, the operation is easy, the POS machine only needs to be clamped on the loading base, and the POS machine can be exchanged and maintained at any time.