The intensity of lightning thermal effect and its influence scope and duration (temperature, time and space scales), are not only the important characteristic parameters for lightning itself, but also the important factors in lightning disaster, lightning protection, lightning chemistry and other fields of applications. Due to the random feature of lightning occurrence time and place, coupled with a strong return stroke current, it is hard to make direct measurement of the temperature in lightning channel. Therefore, remote sensing technology is the only method at present to be adopted. This article summarized the present status of the methods and techniques based on visible and near-infrared spectra analysis applied for lightning channel thermal effect observations both at home and abroad, and provided a description of using a ground-based, multichannel microwave radiometer for this purpose.