The present invention relates to an error compensation and harmonic elimination device in a reactance measurement process. The device comprises a winding circle automatic configuration module, a precision automatic compensation module and a system regulation parameter configuration module. The winding circle automatic configuration module determines the system regulation parameters according to the different transformer winding circles; the precision automatic compensation module performs precision compensation according to the precision of PT and CT collection devices; the system regulation parameter configuration module performs processing according to the output results of the winding circle automatic configuration module and the precision automatic compensation module to realize the error compensation and the harmonic elimination in the reactance measurement process. The error compensation and harmonic elimination device in the reactance measurement process can process the various work conditions and states in the operating environment of transformers with 110KV and more than 110KV and perform various processing of signals to eliminate the false and retain the true so as to improve the test precision and provide more ideal basic signals for the development of the device.