Abstract: In order to study the image distortion and blurring caused by the heat source interference, the level of distortion, blurring and total similarity for the heat source axial displacement imaging were evaluated through using the feature points' average distortion displacement, peak signal to noise ratio, mean squared error and cross correlation coefficient. Furthermore, the correlative discipline between thermal disturbance imaging changes and heat source axial position was gained. Experiment shows that for the heat source axially moving between imaging system and imaging target, the level of distortion, blurring and imaging fault will be worse as the heat source comes closer to the imaging system, and the maximum average distortion displacement is 2.765 3 mm at D=300 mm; as the heat source comes closer to the imaging target, the level of distortion, blurring and imaging fault will be better, and the average distortion displacement decreases to 0.810 2 mm at D=0 mm.