Abstract: Disclosed in the present invention is a visual monitoring method for cross-section temperature fields and radiation characteristics of boiler furnaces by combining radiation images and spectra. Image detectors can be directly inserted into observation holes of a boiler to acquire flame image data, so that when the detection system is applied to a power station boiler, extra holes are not required to be drilled, and therefore, there is no risk that the strength of a furnace wall of the boiler is reduced by drilling holes. According to cross-section temperature fields of a furnace measured by the detection system, the state of combustion in the furnace can be accurately judged, which can play an accurate and effective guiding role in boiler combustion control, and reduce the temperature deviation in each combustion area of the boiler so as to keep the boiler running smoothly, thereby improving the combustion efficiency of the boiler.