The invention provides a defrosting control method for an air conditioner. The air conditioner comprises a compressor, a first four-way valve, an indoor heat exchanger, a throttling device, an outdoor heat exchanger, a refrigerant pipeline, a second four-way valve, an electromagnetic valve and a heat storage device. When the air conditioner is in heating operation, the first four-way valve and the second four-way valve are both converted into a heating mode, a heat storage mode for the heat storage device is controlled to be started and stopped by controlling the on-off state of the electromagnetic valve, and heat stored by the heat storage device is used for achieving a heat source provided when heating and defrosting are simultaneously conducted. When the air conditioner is in defrosting operation, the first four-way valve is kept in the heating mode, the second four-way valve is converted into a refrigerating mode, the electromagnetic valve is opened, refrigerant gas sprayed by the compressor is divided into two branches, the refrigerant gas exhausted by the compressor simultaneously flows to the indoor heat exchanger and the outdoor heat exchanger, in the defrosting process, refrigerant simultaneously flows to the indoor heat exchanger and the outdoor heat exchanger, certain heat exists on the indoor side, cold radiation is not generated, and user comfort is greatly improved.