The invention relates to the technical fields of electric energy metering and measurement, in particular to an on-site calibration system used for GIS station voltage transformer errors. The on-site calibration system used for the GIS station voltage transformer errors comprises a computer, a voltage controlled power source system, an electric parameter measuring and control instrument, a transformer calibrator, a testing transformer and a resonance booster. The voltage controlled power source system and the resonance booster form a programmable voltage regulation power source. The voltage of the programmable voltage regulation power source is controlled to ascend and descend by the electric parameter measuring and control instrument through a DC motor, the electric parameter measuring and control instrument receives electric parameters of the testing transformer and calibration parameters of the transformer calibrator and is connected to the computer through a USB. According to the on-site calibration system used for the GIS station voltage transformer errors, whether a current state is an optimum resonance state or not can be judged, whether the phenomenon of voltage ascent can appear under a high-voltage state can be judged automatically, an operator can be reminded, whether the current state can be boosted to a rated state required by a rule can be judged automatically, and equipment can be protected by controlling disconnection of input voltage of a pressure regulator under abnormal conditions.