A control method for a heating unit disposed within a refrigerating and freezing apparatus, the heating unit comprising a cylinder configured to contain an item to be treated, and an electromagnetic wave generation system of which at least one part is disposed in the cylinder or accessed into the cylinder, and the electromagnetic wave generation system comprising an electromagnetic wave generation module configured to generate an electromagnetic wave signal and a cooling fan configured to cool the electromagnetic wave generation module, wherein the control method comprises: acquiring a forward power signal output from the electromagnetic wave generation module and a reverse power signal returned to the electromagnetic wave generation module; calculating an electromagnetic wave absorption rate of the item to be treated according to the forward power signal and the reverse power signal; and adjusting a rotation speed of the cooling fan according to a power value of the forward power signal, and the electromagnetic wave absorption rate, wherein the step of adjusting a rotation speed of the cooling fan according to a power value of the forward power signal, and the electromagnetic wave absorption rate comprises: matching with the rotation speed of the cooling fan on the basis of a preset rotation speed correspondence relation according to the power value of the forward power signal, and the electromagnetic wave absorption rate, wherein the rotation speed correspondence relation records rotation speeds corresponding to power values in different ranges and electromagnetic wave absorption rates in different ranges; and under the condition that the power values of the forward power signal are the same, the rotation speed of the cooling fan is in negative correlation with an average value of the electromagnetic wave absorption rates in different ranges; and under the condition that the electromagnetic wave absorption rates are the same, the rotation speed of the cooling fan is in positive correlation with an average value of the power values in different ranges. acquiring a forward power signal output from the electromagnetic wave generation module and a reverse power signal returned to the electromagnetic wave generation module; calculating an electromagnetic wave absorption rate of the item to be treated according to the forward power signal and the reverse power signal; and adjusting a rotation speed of the cooling fan according to a power value of the forward power signal, and the electromagnetic wave absorption rate, wherein the step of adjusting a rotation speed of the cooling fan according to a power value of the forward power signal, and the electromagnetic wave absorption rate comprises: matching with the rotation speed of the cooling fan on the basis of a preset rotation speed correspondence relation according to the power value of the forward power signal, and the electromagnetic wave absorption rate, wherein the rotation speed correspondence relation records rotation speeds corresponding to power values in different ranges and electromagnetic wave absorption rates in different ranges; and under the condition that the power values of the forward power signal are the same, the rotation speed of the cooling fan is in negative correlation with an average value of the electromagnetic wave absorption rates in different ranges; and under the condition that the electromagnetic wave absorption rates are the same, the rotation speed of the cooling fan is in positive correlation with an average value of the power values in different ranges. matching with the rotation speed of the cooling fan on the basis of a preset rotation speed correspondence relation according to the power value of the forward power signal, and the electromagnetic wave absorption rate, wherein the rotation speed correspondence relation records rotation speeds corresponding to power values in different ranges and electromagnetic wave absorption rates in different ranges; and under the condition that the power values of the forward power signal are the same, the rotation speed of the cooling fan is in negative correlation with an average value of the electromagnetic wave absorption rates in different ranges; and under the condition that the electromagnetic wave absorption rates are the same, the rotation speed of the cooling fan is in positive correlation with an average value of the power values in different ranges.