Abstract: This invention hereof discloses a refrigerating capacity control device, a test apparatus and a refrigerating control method using the device. The refrigerating capacity control device comprises a compressor (2), a condenser (5), an evaporator (7), a controller (1), a pressure regulating valve (4), a throttling device (6), a control panel (13) for driving a hot-gas valve, and a hot-gas valve (11).