The invention discloses an air conditioner and a control method thereof. The air conditioner comprises a compressor, a reversing assembly, an outdoor heat exchanger, a throttling device, a first indoor heat exchanger, a second indoor heat exchanger, a first control valve and a second control valve, wherein the first indoor heat exchanger and the second indoor heat exchanger are arranged in the same indoor unit and connected in parallel; when the air conditioner is in a refrigeration mode and using of the second indoor heat exchanger needs to be stopped, the first control valve is closed, and the second control valve is in the state of blocking coolants from flowing towards the second indoor heat exchanger after a set period of time; and when the air conditioner is in a heating mode and using of the second indoor heat exchanger needs to be stopped, the heating mode is switched to be the refrigeration mode, then, the first control valve is closed, the refrigeration mode is switched to be the heating mode after a set period of time, and the second control valve is in the state of blocking the coolants from flowing towards the second indoor heat exchanger. According to the air conditioner provided by the invention, the problem that the heat exchange area of an indoor heat exchanger is too large can be solved, and the problem that the coolants are accumulated in a part of shielded indoor heat exchangers in the correlation technique is also solved.