A heat exchanger, comprising: a first pipe and a second pipe, wherein the first pipe comprises a circumferential wall and a main channel surrounded by the circumferential wall, the heat exchanger further comprises an inlet/outlet pipe, and the inlet/outlet pipe is connected to the first pipe; a plurality of heat exchange tubes, wherein the heat exchange tube is connected to the first pipe and the second pipe, the heat exchange tube comprises a plurality of channels arranged to be spaced apart, the channel is connected to the first pipe and the second pipe, flow cross-sectional areas of every two of at least three channels in the plurality of channels are not equal to each other on a cross section of the heat exchange tube, and the plurality of channels comprise a first channel and a second channel; and on the cross section of the heat exchange tube, a flow cross-sectional area of the first channel is greater than a flow cross-sectional area of another channel different from the first channel in the plurality of channels, and a flow cross-sectional area of the second channel is less than a flow cross-sectional area of another channel different from the second channel in the plurality of channels; the heat exchanger being characterized by a first member, wherein the first member is located in the main channel of the first pipe, the first member extends by a specific distance along a length direction of the first pipe, the main channel comprises a first flow channel and a second flow channel, the first member is located between the first flow channel and the second flow channel, the first flow channel is connected to the inlet/outlet pipe, the second flow channel is connected to the heat exchange tube, the first member comprises a plurality of through-holes, and the through-hole connects the first flow channel and the second flow channel, wherein the flow cross-sectional area of the first channel on the cross section of the heat exchange tube is A1, the flow cross-sectional area of the second channel on the cross section of the heat exchange tube is A2, and the A1 and A2 satisfy the following expression: 0.15 ≤ (A1-A2)*N/A3 ≤ 3.8, wherein A3 is a sum of flow cross-sectional areas of the plurality of through-holes of the first member, and N is a quantity of the heat exchange tubes connected to the main channel. a first pipe and a second pipe, wherein the first pipe comprises a circumferential wall and a main channel surrounded by the circumferential wall, the heat exchanger further comprises an inlet/outlet pipe, and the inlet/outlet pipe is connected to the first pipe; a plurality of heat exchange tubes, wherein the heat exchange tube is connected to the first pipe and the second pipe, the heat exchange tube comprises a plurality of channels arranged to be spaced apart, the channel is connected to the first pipe and the second pipe, flow cross-sectional areas of every two of at least three channels in the plurality of channels are not equal to each other on a cross section of the heat exchange tube, and the plurality of channels comprise a first channel and a second channel; and on the cross section of the heat exchange tube, a flow cross-sectional area of the first channel is greater than a flow cross-sectional area of another channel different from the first channel in the plurality of channels, and a flow cross-sectional area of the second channel is less than a flow cross-sectional area of another channel different from the second channel in the plurality of channels; the heat exchanger being characterized by a first member, wherein the first member is located in the main channel of the first pipe, the first member extends by a specific distance along a length direction of the first pipe, the main channel comprises a first flow channel and a second flow channel, the first member is located between the first flow channel and the second flow channel, the first flow channel is connected to the inlet/outlet pipe, the second flow channel is connected to the heat exchange tube, the first member comprises a plurality of through-holes, and the through-hole connects the first flow channel and the second flow channel, wherein the flow cross-sectional area of the first channel on the cross section of the heat exchange tube is A1, the flow cross-sectional area of the second channel on the cross section of the heat exchange tube is A2, and the A1 and A2 satisfy the following expression: 0.15 ≤ (A1-A2)*N/A3 ≤ 3.8, wherein A3 is a sum of flow cross-sectional areas of the plurality of through-holes of the first member, and N is a quantity of the heat exchange tubes connected to the main channel.