The invention provides a method for controlling operation of an air conditioner in a mute mode. In the method, the air conditioner can automatically enter a mute control mode according to the change of outdoor environment temperatures, so that automatic control is realized. The method comprises the following steps of: calculating the time when the air conditioner starts to operate in the mute mode; during refrigeration, controlling the relation of the common target evaporation temperature during operation of an air conditioning system in an unmute mode and a new target evaporation temperature; and during heating, controlling the relation of the common target condensation temperature during operation of the air conditioning system in the unmute mode and a new target condensation temperature. By the method, the frequency and the noise of the air conditioning system are reduced, and the air conditioning system operates in the mute mode; and the change of the environment temperature is scientifically calculated, the air conditioning system is intelligently controlled, an outdoor unit is automatically controlled, and operation such as dial-up setting and the like is not required, so requirements of customers on the effect of the air conditioner can be met, requirements of the customers on low noise can also met, and system failures can be avoided.