A refrigeration cabinet system, comprising: one or more indoor units (21, 22, 23), each of which comprises: an indoor unit inlet (211, 221), an indoor unit outlet (212, 222), an expansion valve (213, 223) between the indoor unit inlet and the indoor unit outlet, an evaporator (214, 224) downstream of the expansion valve, and a display cabinet cooled by the evaporator; and an outdoor unit, which comprises: an outdoor unit inlet, an outdoor unit outlet, an inverter compressor between the outdoor unit inlet and the outdoor unit outlet, a condenser downstream of the inverter compressor, a controller for controlling an operating frequency of the inverter compressor, and a pressure sensor on a suction side of the inverter compressor; wherein the outdoor unit outlet is connected to each indoor unit inlet (211, 221) through a pipeline, and each indoor unit outlet (212, 222) is connected to the outdoor unit inlet through pipelines (321, 322); and wherein the controller is connected to the pressure sensor to obtain pressure information on the suction side of the inverter compressor, and the controller is configured to change the operating frequency of the inverter compressor based on the pressure information to control the pressure on the suction side of the inverter compressor to be within a certain range; characterised in that the controller is configured to, by changing the operating frequency of the inverter compressor to control the pressure on the suction side of the inverter compressor to be within a certain range, maintain a saturated evaporation temperature of each indoor unit (21, 22, 23) to be within a range of -1.5°C to +1.5°C. one or more indoor units (21, 22, 23), each of which comprises: an indoor unit inlet (211, 221), an indoor unit outlet (212, 222), an expansion valve (213, 223) between the indoor unit inlet and the indoor unit outlet, an evaporator (214, 224) downstream of the expansion valve, and a display cabinet cooled by the evaporator; and an outdoor unit, which comprises: an outdoor unit inlet, an outdoor unit outlet, an inverter compressor between the outdoor unit inlet and the outdoor unit outlet, a condenser downstream of the inverter compressor, a controller for controlling an operating frequency of the inverter compressor, and a pressure sensor on a suction side of the inverter compressor; wherein the outdoor unit outlet is connected to each indoor unit inlet (211, 221) through a pipeline, and each indoor unit outlet (212, 222) is connected to the outdoor unit inlet through pipelines (321, 322); and wherein the controller is connected to the pressure sensor to obtain pressure information on the suction side of the inverter compressor, and the controller is configured to change the operating frequency of the inverter compressor based on the pressure information to control the pressure on the suction side of the inverter compressor to be within a certain range; characterised in that the controller is configured to, by changing the operating frequency of the inverter compressor to control the pressure on the suction side of the inverter compressor to be within a certain range, maintain a saturated evaporation temperature of each indoor unit (21, 22, 23) to be within a range of -1.5°C to +1.5°C.