The invention provides cable trench monitoring and early warning equipment. By means of the monitoring and early warning equipment, information of smoke, gas concentration, temperature, liquid level and the like in a cable trench can be comprehensively monitored in real time, and it is convenient for a worker to conduct management and maintenance on a transformer substation. The equipment comprises a box body, monitoring devices and an RS485 communication interface are arranged on the box body, and the monitoring devices at least comprise a Pt100 temperature sensor, an LDK plug-in liquid levelsensor, an HLPLANAR infrared gas concentration sensor, an STP-MW168-9v smoke sensor, a processing unit and a power supply module; the RS485 communication interface is used for enabling the monitoringdevices to be connected with the monitoring terminal of a control end, and transmitting abnormal data and early warning information to the monitoring terminal based on enable signals generated by themonitoring devices.