Control method and control device for defrosting without shutdown, and air conditioner

The invention provides a control method and control device for defrosting without shutdown, and an air conditioner. The control method for defrosting without shutdown comprises the steps of detecting temperatures T1 and T2 of a first outdoor heat exchanger and second outdoor heat exchanger when the air conditioner is in a heating mode; recording times t1 and t2 of the first outdoor heat exchanger and second outdoor heat exchanger being in the heating mode; judging whether T1 and t1 reach a defrosting condition and whether T2 and t2 reach the defrosting condition; and controlling the first outdoor heat exchanger or the second outdoor heat exchanger to defrost according to a judgment result. According to the technical scheme of the method and the device provided by the invention, the purpose that a compressor does not shut down and an indoor machine generates heat continuously during a defrosting process of the outdoor heat exchanger is achieved, defrosting speed is increased, and thus defrosting time is saved;