The invention relates to a double closed loop control system and a double closed loop control method of dynamic demand of an electric furnace. Fluctuation of electricity utilization load of an electric furnace is reduced and electricity utilization efficiency of the electric furnace is improved. The system comprises an offline decision module, an online optimization setting module, a setting value dynamic adjustment module and a control module. The electrical load setting value is adjusted in a closed loop manner according to a feedback value of the electrical load of the electric furnace and the setting value is transmitted to a controller to adjust rising and descending of three-phase electrode of the electric furnace in a closed loop manner, so it is ensured that the actual electrical load of the electric furnace is adjusted to an expected level in a dynamic and undetermined environment.