An electronic device protecting casing with heating function includes: a casing; a battery box within the casing; an interior of the battery box being arranged with a battery, a back side of the battery box being formed with an opening for receiving the battery; an outer cover serving to seal the opening; an inner side of the outer cover being formed with a heat isolation sheet; a heating unit being installed within the casing for heating the tablet computer; the heating unit including an electric heating plate. When power of the battery is transferred to the electric heating plate, the electric heating plate generates heat power and then transfers the power to the tablet computer for heating it; and a control circuit is installed within the casing; the electric heating plate is connected to the battery through a control switch; and the control circuit is connected to the control switch.