The invention provides a temperature monitoring system of a switch cabinet. The temperature monitoring system of the switch cabinet comprises a temperature detection device, a processing module and an alarm module. The temperature detection device is used for detecting the temperature of electric devices of the switch cabinet and outputting the temperature values of the electric devices to the processing module. The processing module is used for comparing the temperature values with a preset temperature upper limit value and outputting alarm signals to the alarm module when the temperature values exceed the preset temperature upper limit value. The alarm module sends alarm information to operation and maintenance staff in time after receiving the alarm signals to inform the operation and maintenance staff of the fact that the temperature of the electric devices in the switch cabinet is abnormal. The abnormal temperature shows that maybe, the electric devices will break down, and the operation and maintenance staff can repair or maintain the switch cabinet in time according to the alarm information. Due to the fact that the temperature monitoring system can carry out continuous monitoring on the temperature of the electric devices in the switch cabinet, the problem that uninterrupted monitoring cannot be carried out through manual routing inspection is solved. Therefore, it can be better guaranteed that the switch cabinet can run stably and safely.