A CT self-powered switch cabinet detection device comprises a temperature, humidity and current measurement module for measuring the temperature and current of a switch plum blossom contact and the environment temperature and humidity data in a switch cabinet; the ozone measuring module is used for measuring ozone concentration data in the switch cabinet; a first communication module; a second communication module; the power taking module is used for automatically sensing energy from the high-voltage electrified equipment to supply power to the temperature, humidity and current measuring module, the ozone measuring module, the first communication module and the second communication module; the metal annular bandage, the temperature, humidity and current measurement module, the ozone measurement module and the power taking module are all installed on the annular bandage, and the two ends of the metal annular bandage are connected through buckles to form a closed loop to be clamped to the edge of the switch plum blossom contact. The device has the advantages that the temperature and current of the switch contact, and the environment temperature and humidity and ozone content of the switch operation can be accurately measured, so as to realize the evaluation of the insulation state.