The invention discloses an online monitoring system for infrared thermal imaging of a converting station. The system comprises an online infrared thermal imaging instrument, a view screen monitoring and processing module, an infrared image information processing module and a system management and maintenance module, wherein the view screen monitoring and processing module comprises a communication and control subsystem and an infrared imaging and temperature measuring subsystem; the communication and control subsystem is used for controlling a field online infrared thermal imaging instrument, a visible light CCD (Charge Coupled Device) and a tripod head servo and setting and controlling a data link; the infrared imaging and temperature measuring subsystem comprises a temperature measuring, recording, alarming and short message platform system for realizing temperature measurement, alarming and transmission of alarm information through a short message platform; the infrared image information processing module comprises an infrared image analysis system, a failure auxiliary diagnosis system and an infrared and visible light video processing system; and the system management and maintenance module comprises an equipment thermal failure typical infrared image library management system, a management inquiry, statistic and report system and an interface system for an extant service system. By means of the online monitoring system in the invention, the defects of portable infrared imaging are overcome, artificial detection is combined with system detection, real-time monitoring of electric equipment is realized, and infrared thermal image monitoring of a monitored range or specified target equipment as well as data acquisition and recording, storage and analysis of a temperature field are ensured. The system has the characteristics of automatic routing inspection, automatic pre-warning, accuracy, high speed and remote monitoring.