<p>PURPOSE: An air conditioner and a control method thereof are provided to maintain the refrigerant pressure of an outdoor unit within a range of high or low pressure by controlling the opened level of an electronic expansion valve. CONSTITUTION: An air conditioner comprises an outdoor unit(200) and an indoor unit(100). The outdoor unit comprises a compressor(260) and an outdoor expansion valve(280). The indoor unit comprises an indoor expansion valve(140). The air conditioner measures the pressure of refrigerant discharged from the compressor in a cooling operation. If the pressure of the refrigerant is below a predetermined value, the opened level of one or more of the outdoor and indoor expansion valves is controlled to increase the pressure of the refrigerant to over the predetermined value.</p>
