The metrical software of atmospheric coherence length instrument is upgraded. The image processing algorithm is ameliorated by the software and the efficiency target identification is improved. The area of image processing is doubled, and the stabilization of system is improved. Self-adaptation of the image brightness and contrast is realized in complex environment. Parameters of target identification algorithm can be adjusted by the atmospheric coherence length instrument real-time based on the changes of the brightness of background, so faculae can be captured continuously. The software’s auto tracking is realized based on the threshold algorithm, and the auto level of instrument is improved.