The invention provides a building block type test device for the field calibration of a GIS type current transformer. The device comprises a voltage regulator power supply, a compensation capacitor group, a large current generator group, a transformer calibrator, a standard current transformer and a current transformer to be measured. An output end of the voltage regulator power supply is connected to an input end of the large current generator group. An output end of the large current generator group is connected to one end of a measured current transformer, and the primary current rising operation of the measured current transformer is carried out. The other end of the current transformer is connected to one end of the standard current transformer, and the other end of the standard current transformer is connected to another output end of the large current generator group. An output end of the transformer calibrator is connected to an input end of the standard current transformer. The compensation capacitor group is connected to an output end of the voltage regulator power supply. The building block type test device is more versatile, and the large current generator group and thecapacitor group on the device can be adjusted to be adapted to a variety of devices.