An ejector refrigeration system, comprising: a compressor, a heat-extraction heat exchanger, an ejector, a separator, a first throttling element, and a heat-absorption heat exchanger that are connected through pipelines, the ejector having a main flow inlet connected to the heat-extraction heat exchanger, and further having a secondary flow inlet and an ejector outlet; the separator having a separator inlet connected to the ejector outlet, a separator liquid outlet connected to the first throttling element, and a separator gas outlet connected to a gas inlet of the compressor; characterised in that turn-on and turn-off of a first flow path connecting the heat-absorption heat exchanger and the secondary flow inlet of the ejector and a second flow path connecting the heat-absorption heat exchanger and the gas inlet of the compressor are controllable; and further comprising: a three-way valve connected to an outlet of the heat-absorption heat exchanger, the secondary flow inlet of the ejector, and the gas inlet of the compressor respectively, wherein the three-way valve is switched to alternatively turn on the first flow path or the second flow path; and a second throttling element disposed between the separator gas outlet and the gas inlet of the compressor, wherein the separator gas outlet is connected to an intake port of the compressor through the second flow path, wherein the second throttling element is disposed between the separator gas outlet and the second flow path a compressor, a heat-extraction heat exchanger, an ejector, a separator, a first throttling element, and a heat-absorption heat exchanger that are connected through pipelines, the ejector having a main flow inlet connected to the heat-extraction heat exchanger, and further having a secondary flow inlet and an ejector outlet; the separator having a separator inlet connected to the ejector outlet, a separator liquid outlet connected to the first throttling element, and a separator gas outlet connected to a gas inlet of the compressor; characterised in that turn-on and turn-off of a first flow path connecting the heat-absorption heat exchanger and the secondary flow inlet of the ejector and a second flow path connecting the heat-absorption heat exchanger and the gas inlet of the compressor are controllable; and further comprising: a three-way valve connected to an outlet of the heat-absorption heat exchanger, the secondary flow inlet of the ejector, and the gas inlet of the compressor respectively, wherein the three-way valve is switched to alternatively turn on the first flow path or the second flow path; and a second throttling element disposed between the separator gas outlet and the gas inlet of the compressor, wherein the separator gas outlet is connected to an intake port of the compressor through the second flow path, wherein the second throttling element is disposed between the separator gas outlet and the second flow path a three-way valve connected to an outlet of the heat-absorption heat exchanger, the secondary flow inlet of the ejector, and the gas inlet of the compressor respectively, wherein the three-way valve is switched to alternatively turn on the first flow path or the second flow path; and a second throttling element disposed between the separator gas outlet and the gas inlet of the compressor, wherein the separator gas outlet is connected to an intake port of the compressor through the second flow path, wherein the second throttling element is disposed between the separator gas outlet and the second flow path