The invention discloses a differential driving and protecting device in a screw discharging centrifuge, which can protect a differential mechanism and comprises a location movable disc arranged on the input shaft of the differential mechanism and a location static disc arranged on the engine body, wherein the location movable disc and the location static disc are connected through a location safety pin. When a torque of a barrate and a scraping spiral is enlarged to a certain level caused by calking of the centrifuge or other reasons, the location safety pin is broken, the location movable disc can rotate along with the input shaft to lead the barrate and the scraping spiral to perform constant speed rotation after being free of the restrain of the input shaft, therefore, the differential mechanism of the centrifuge can be well protected without relative torque.