The invention provides a current comparator calibration system and a current comparator calibration method. The current comparator calibration system comprises an ampere-turn difference measurer, a standard current comparator and a calibrated current comparator. The primary winding of the standard current comparator and the primary winding of the calibrated current comparator are connected with a power supply. The secondary winding of the standard current comparator and the secondary winding of the calibrated current comparator are connected with the ampere-turn difference measurer. According to the current comparator calibration method, an error of an initial transformation ratio is determined through a traditional current ratio standard self-calibrating line; a secondary current ampere-turn difference between an etalon and a calibrated current proportion standard is measured through the ampere-turn difference measurer; and transmission of a current proportional value to higher transformation ratio is realized. The current comparator calibration system and the current comparator calibration method have advantages of ensuring high accuracy of calibrated current, realizing no requirement for manual error current adjustment, greatly reducing workloads in adjustment and wiring, reducing an uncertainty loss link in a magnitude transmission process, and preventing an additional impedance which forms the etalon and the calibrated current proportional standard.