The utility model provides a turbo generator shaft current and axis voltage on -line monitoring device for on sending out motor body and connect the turbo generator of steam turbine and exciter respectively through the macroaxis, and be equipped with vapour end ground loop on one side of the steam turbine, including data processing module, data analysis's main control unit and the alarm module ofwarning who gathers the first of steam turbine and generator macroaxis earth current and the 2nd current transformer, the voltage collector who gathers excitation machine side axis voltage, signal filtering processing and conversion respectively. A current transformer cup joints and holds ground loop and voltage collector to connect the macroaxis of excitation machine side after report to the police behind the data processing module entering main control unit analytical judgement in alarm module in epaxial greatly, the 2nd current transformer access vapour of turbine machine side. Implement the utility model discloses, overcome only adopt macroaxis earth current for differentiate that the shaft current level brings not enough with adopt the great shaft current horizontally defect of the unable reaction pair generator harm of axis voltage alone.