The invention relates to an electrical field, and provides a slow-temperature-reduction power distribution cabinet and a protecting method of an electrical element. The slow-temperature-reduction power distribution cabinet comprises a cabinet body which is internally provided with the electrical element. A storage battery is mounted in the cabinet body. The storage battery is connected with a heating unit through a control unit. The cabinet body is internally provided with a temperature measuring device which is connected with the control unit. When quick temperature reduction of the electrical element or power-off of the power distribution cabinet occurs, the control unit makes the heating element perform heating. The cabinet body is internally provided with a power line which is connected with the storage battery through the control unit. The control unit is provided with a setting unit. The power distribution cabinet is internally provided with a circuit breaker which is connected with the control unit. According to the protecting method of the electrical element, the heating component is mounted at the periphery of the electrical element; when the temperature of the electric element reduces quickly or power-off occurs, the heating element performs heating for compensation, thereby realizing slow temperature reduction of the electrical element. The slow-temperature-reduction power distribution cabinet and the protecting method of the electrical element have advantages of reducing electrical element service life reduction caused by power-off and overhigh temperature reduction speed, and improving use effect.