The invention relates to a real-time controllable derotation flow vibration damper of a seal system in an impeller machine which is mainly used for reducing the vibration of a rotor seal system or vanes, and is mainly applied to the industrial rotating machines like a compressor, a steam turbine, a gas turbine, a turbopump, and the like. The real-time controllable derotation flow vibration damper of a seal system in an impeller machine comprises a real-time signal detecting and analyzing system, as well as an actuating system; the invention is characterized in that the real-time signal detecting and analyzing system comprises an eddy-current displacement sensor, a pressure sensor, a connection terminal, a signal modulating module, a data collection card and a computer; the actuating system of the controllable derotation flow vibration damper comprises an air pump, a storage tank, an electric adjusting valve/electromagnetic adjusting valve, a multi-way joint, a pipeline and a nozzle. Compared with the existing derotation flow technology, the device carries out adjusting and controlling by continuously detecting the changes of the parameters like the vibration size, the medium pressure and flux of the system in real time, has a good vibration damping effect, can not affect the running efficiency of a machine unit, and more importantly, can not cause the vibration of the machine unit.