Scene match arithmetic which has high dependability and precision is the most important factor of image navigation for independent navigation aircraft. The current study has researched into gray distortion of scene match images, and brought forward the emendation method based on the histogram similar transform which can improve the veracity and reliability of scene matching arithmetic. For different external condition and imaging apparatus, there are many gray differences in images participating in scene match, which will affect the scene match robustness seriously. Via adjusting the histogram of scene match images to make them identical, this research eliminated the gray distortion. As a result, the scene match images histogram similar coefficients were all more than 0.95. 10 300 true outfield scene matching orientation experimentations have testified that the pretreatment method for gray images based on histogram can effectively eliminate the gray distortion and decrease the repetitious patterns caused by gray distortion. The success ratio of scene match has reached the level of 99.98%, which has met the high dependability need of projects.