The invention discloses a heat treatment method for amorphous alloy iron cores. The method includes the steps that firstly, the amorphous alloy iron cores are fed into a furnace, a purification nitrogen program is started, and nitrogen is led into the furnace; secondly, when the oxygen content in a furnace chamber of the annealing furnace is less than 10%, a heating program is carried out; thirdly, a rotating magnetic field is applied when the temperature of the iron cores reaches 200 DEG C, and the planes of the iron cores are always kept parallel to the direction of the magnetic field during rotation; fourthly, heating is continued, and heat preservation is started when all the iron cores reach the optimal annealing temperature which means that the temperatures of the iron cores are controlled to be 320-370 DEG C; and fifthly, heating is stopped after the heat preservation is completed, a cooling program is started, and after the temperature of the iron cores is reduced to the room temperature, the iron cores are discharged out of the furnace to complete heat treatment of the amorphous alloy iron cores. The rotary magnetic field is applied in the annealing process, the advantages of transverse magnetic field processing and longitudinal magnetic field processing are integrated, the loss is reduced while the magnetic conductivity of the amorphous alloy iron cores is increased, and the magnetic property of amorphous alloy can be obviously improved.