The invention discloses a device for verifying secondary wiring automatic switching by a program-controlled three-phase combined instrument transformer, and the device comprises a wiring box, a calibrator, a secondary side of a standard instrument transformer and a control device, wherein the wiring box comprises a verification circuit, the verification circuit comprises three current load boxes,three voltage load boxes and a plurality of relays, each verification port of the verification circuit is connected to a connector for inserting and removing a secondary voltage terminal and a secondary current terminal of an instrument transformer to be tested; the secondary side of the standard instrument transformer is connected to the calibrator by the wiring box to provide a measurement signal required for the verification; and the control device realizes the control of the relays in the wiring box to realize the switching of the verification mode. By setting the connector at each verification port in the verification circuit of the wiring box, the secondary side of the instrument transformer to be tested can be quickly inserted and removed, and the work efficiency and the safety index of the verification process are improved, so as to meet increasingly high requirements of the development of the three-phase combined instrument transformer for the verification work.