“…However, most of the existed temperature and emissivity separation algorithms [3], [4], [5], [6], [7], [8], [9], [10], [11], [12] designed for processing thermal infrared data will be out of use when it was used to process the mid-infrared data. In order to avoid the uncertainty of surface temperature determination from the difference of soil radiance under sun-shining and sun-shaded condition in the four step method [13] due to the unknown soil emissivity before measurements, we obtains soil thermal infrared emissivity and temperature with high accuracy by utilizing the ISSTES algorithm [11] from thermal infrared data, then introducing the soil temperature into soil mid-infrared emissivity extraction, reducing the number of parameters need to be inversed in mid-infrared, forming redundant observation, and using the least square method to solve the equation at last. Assuming the environmental radiance doesn't change during the measurements, we can get the equation 1 , , 1 , , With the least square method, we acquire 3 , 1 4 , , 2 , , , …”