The invention discloses a waste heat recovery system and method of an electric furnace, and belongs to the field of waste heat recovery of industrial furnaces. The system comprises an electric furnaceevaporation cooling furnace lid, a waste steel pre-heating device, an evaporation cooling elbow flue, a combustion settling chamber, a smoke waste heat boiler and a dust removal and smoke discharge device which are sequentially connected. An evaporator, an economizer and a soft water heater are arranged in the smoke waste heat boiler. The system further comprises a soft water tank, a deaerator, amedium-pressure heat storage station, a low-pressure heat storage station, a low-pressure steam pocket and a medium-pressure steam pocket. According to the waste heat recovery system and method, themedium-pressure steam pocket is arranged to supply water to the evaporator of the smoke waste heat boiler, the low-pressure steam pocket supplies water to the electric furnace evaporation cooling furnace lid and the evaporation cooling elbow flue, and waste heat of the electric furnace lid and primary smoke waste heat can be recycled to generate low-pressure steam and medium-pressure steam; and byarranging the economizer and the soft water heater in the smoke waste heat boiler, the heat exchange temperature difference between smoke and the water can be increased, the smoke cooling speed can be increased, and restraining of synthesis of dioxin can be facilitated.