The verification device of high-voltage electricity meter has the ability to output high voltage and large current. In order to verify high-voltage electricity meters with different current specifications, it is necessary to output current in accordance with the verification regulations. At present, most calibration devices need to manually change the gear wiring of the current riser or current transformer in the state of shutdown and power failure, so as to output the current value that meets the accuracy requirements. This paper presents an automatic controller for intelligent switching of current gear, and introduces its working principle, software and hardware design in detail. Based on the synchronous switching of multiple magnetic holding relays, the controller can control the continuous output of any value within the maximum allowable current without stopping the calibration device, which effectively improves the safety, reliability and rapidity of automatic calibration.