The invention discloses a method and device for controlling heating of a sucker rod, and belongs to the field of oil field exploitation. The method comprises the steps that the temperature value of heavy oil at a wellhead of an oil well is acquired; when the temperature value is smaller than the maximum preset heavy oil temperature value and larger than a set value of the heavy oil temperature, the current balance degree and the current maximum load of a pumping unit of the oil well are obtained; the balance degree deviation is obtained; the maximum load deviation is obtained, wherein the maximum load deviation is the difference value between the current maximum load of the pumping unit and the historical maximum load of the pumping unit; according to the balance degree deviation and the maximum load deviation, the temperature deviation of the heavy oil in a shaft is determined on the basis of the fuzzy control method; the heating duration of the sucker rod of the pumping unit is determined on the basis of the PID control method according to the heavy oil temperature deviation in the shaft, the temperature value and the heavy oil temperature set value; on the basis of the heating duration, heating of the sucker rod is controlled. The method and device can ensure the accuracy of the heating duration, so that the recovery rate of the heavy oil is guaranteed, and waste of electricenergy is avoided.