The present invention provides a rotation direction detection device, method and system of a pumped storage unit. The rotation direction detection device comprises a simulation measurement module and a speed measuring toothed wheel which is installed on the large shaft of the pumped storage unit of a pumped storage power station; the speed measuring toothed wheel is of an equidistantly-cut circular toothed structure and includes tooth tops and tooth bottoms; and the simulation measurement module comprises a plurality of probes which point to the axis of the large shaft and are used for outputting pulse signals, a simulation measurement component which is connected with the plurality of probes and is used for generating a pulse matrix based on the pulse signals and outputting a rotation detection result of the pumped storage unit according to the pulse matrix. According to the rotation direction detection device, method and system of the pumped storage unit of the present invention, the rotation direction of the unit is determined through analyzing a dynamic relationship between the rotational displacement of the speed measuring geared wheel arranged on the large shaft of the pumped storage unit of the pumped storage power station and the speed measuring probes, and therefore, the operating conditions of the unit can be determined accurately through detecting the rotation direction of the unit in real time.