Current transformer (CT) has been widely used in current ratio transformation. Normally the accuracy can’t exceed 0.01%. Some more accurate current ratio devices, such as two-stage current transformer and compensated current comparator, can only be used in the traceability or distribution area of current ratio quantity of power frequency due to some limitations. In view of this situation, a current comparator with electronic compensation (ECCC) using electronic circuit to compensate the magnetizing current of the core was developed. The principle, theoretical analysis of the error, and the calibration tests are presented in the paper. The results showed that the ECCC fulfills the requirements of the accuracy class of 0.0005. It can be used either as a high accuracy current ratio standard, or a normal CT in power frequency current measurement area where high accuracy is needed.