A gas-liquid separator, wherein the gas-liquid separator comprises: a first cylinder , a second cylinder , a heat exchange pipe , a flow guide pipe , a distribution portion , and a lower sealing cover , wherein the first cylinder is located at an inner side of the second cylinder , the gas-liquid separator has a first chamber and a second chamber which are in communication with each other, the first chamber is located in the second cylinder and outside the first cylinder , the second chamber at least comprises a space located inside the first cylinder , the heat exchange pipe is located outside the first cylinder , and the heat exchange pipe is disposed in the first chamber ; the distribution portion is fixed to the second cylinder , the distribution portion has a first passage , the flow guide pipe is fixed to the distribution portion , one end of the first passage is in communication with one end of the flow guide pipe , the other end of the flow guide pipe is in communication with the first chamber , the other end of the first passage is in communication with the first chamber ; the lower sealing cover is fixed to the second cylinder , the lower sealing cover is located at the other side relatively away from the distribution portion , the gas-liquid separator further comprises a flow passage , at least part of the flow passage is located in the lower sealing cover , the flow passage is in communication with the first chamber , and the flow passage is in communication with the second chamber through the first chamber , characterized in that , the heat exchange pipe comprises a first collecting pipe , a second collecting pipe and a plurality of flat tubes arranged in parallel with each other, one end of the flat tubes is connected with the first collecting pipe , the other end of the flat tubes is connected with the second collecting pipe , and the first collecting pipe and the second collecting pipe are arranged approximately in parallel with each other. a first cylinder , a second cylinder , a heat exchange pipe , a flow guide pipe , a distribution portion , and a lower sealing cover , wherein the first cylinder is located at an inner side of the second cylinder , the gas-liquid separator has a first chamber and a second chamber which are in communication with each other, the first chamber is located in the second cylinder and outside the first cylinder , the second chamber at least comprises a space located inside the first cylinder , the heat exchange pipe is located outside the first cylinder , and the heat exchange pipe is disposed in the first chamber ; the distribution portion is fixed to the second cylinder , the distribution portion has a first passage , the flow guide pipe is fixed to the distribution portion , one end of the first passage is in communication with one end of the flow guide pipe , the other end of the flow guide pipe is in communication with the first chamber , the other end of the first passage is in communication with the first chamber ; the lower sealing cover is fixed to the second cylinder , the lower sealing cover is located at the other side relatively away from the distribution portion , the gas-liquid separator further comprises a flow passage , at least part of the flow passage is located in the lower sealing cover , the flow passage is in communication with the first chamber , and the flow passage is in communication with the second chamber through the first chamber , characterized in that , the heat exchange pipe comprises a first collecting pipe , a second collecting pipe and a plurality of flat tubes arranged in parallel with each other, one end of the flat tubes is connected with the first collecting pipe , the other end of the flat tubes is connected with the second collecting pipe , and the first collecting pipe and the second collecting pipe are arranged approximately in parallel with each other. <EOS>