The invention provides a steam compression system. The steam compression system comprises a centrifugal steam compressor, a screw steam compressor, a high-temperature water pump and a water pump, wherein a first valve and a water draining separator are arranged at an inlet of the centrifugal compressor; a first steam-liquid separator and a first pressure stabilizing valve are arranged at an outlet of the centrifugal compressor; a second steam-liquid separator and a second pressure stabilizing valve are arranged at an outlet of the screw compressor; the high-temperature water pump communicates with a water outlet of the first steam-liquid separator and a water spraying cooling opening of the screw compressor; the water pump communicates with a water outlet of the second steam-liquid separator and an outlet of the centrifugal compressor; a softened water tube is arranged at an inlet of the high-temperature water pump; and the softened water tube also communicates with an inlet of the water pump. The invention further provides a working method of the steam compression system. Steam compression requirements of large flow, high pressure ratio (high saturation temperature rise) and low exhaust steam temperature can be met, heat source steam capable of replacing boiler steam is provided, the steam compression system can be combined to a mechanical steam recompression system, and the purpose of industrial energy conservation is achieved.