Abstract: The present invention provides a combined scale inhibitor and scale inhibiting device. The combined scale inhibitor contains organophosphorus filter materials, ceramic filter materials and polyphosphate filter materials. The organophosphorus filter materials are the granular filter materials of liquid organophosphorus scale and corrosion inhibitor while the said ceramic filter materials are the granular filter materials containing oxide ceramic powder. The said scale inhibiting device is comprised of a tank, a water inlet, a water outlet, an organophosphorus filter material layer, a ceramic filter material layer and a polyphosphate filter material layer in the said tank. The said organophosphorus filter material layer contains organophosphorus filter materials, which are the granular filter materials of liquid organophosphorus scale and corrosion inhibitor. The said ceramic filter material layer contains ceramic filter materials, which are the granular filter materials containing oxide ceramic powder.