The invention relates to the technical field of air conditioning, in particular to an air conditioner and a refrigeration control method thereof. Bypass branches are in parallel connection with a pipe section between an outdoor heat exchanger and a throttling device of the air conditioner; a first switch valve and a refrigerant storage device are arranged on each bypath branch along the direction from the outdoor heat exchanger to the throttling device sequentially. When a high pressure value of a refrigerant in the air conditioner is too high, excessive refrigerant in a refrigeration loop of the air conditioner is stored through the bypath branches, and the pressure of the refrigerant in the refrigeration loop is reduced till the high pressure value of the refrigerant meet the requirement. Therefore, the air conditioner can refrigerate normally in a high temperature environment or even in a superhigh temperature environment, and the problem that a user fails to refrigerate in a high temperature environment is solved effectively.