The invention discloses a device for detecting an alternating current transformer and a secondary circuit. The device comprises a primary current acquisition sub-device and a secondary circuit detection sub-device. Primary current data acquired by the primary current acquisition sub-device are transmitted to a main processor in a wireless communication mode, meanwhile, secondary currents and secondary terminal voltages acquired by the secondary circuit detection sub-device can also be transmitted to the main processor, operation processing is conducted on the received data through the main processor, and then the alternating current transformer and the secondary circuit are detected. It can be seen that the device can detect the alternating current transformer and the secondary circuit at the same time, a man-made communication link in the prior art is omitted, electric power accidents caused by communication errors are effectively avoided, and detection integrity and correctness of the alternating current circuit are guaranteed.