Uncooled infrared thermal imagers have the features of low price, low weight, low power dissipation, small size and reliability etc.. An uncooled infrared thermal imager with an infrared micro-bolometer focal plane array is used to analyze the temperature distribution and lesions of human bodies. Because infrared grey scale images have lower contrast and the grey scales of the images of different parts of a human body are different, the pseudo-color images obtained by the infrared thermal imager are processed by using an adaptive threshold processing method. The processing results are of great convenience for analyzing the location and size of lesions.