Abstract: For the priority order of the multiplication constant correction and the gray correction, a gray-scale priority calibration model was proposed. Firstly, the main error sources of pulsed ranging were analyzed. Then the existence of the multiplication constant and distance correction table and the influence of gray scale on the multiplication constant were verified. Then the consistency of the distance correction table at different distances was verified. Finally, a gray-scale prionty distance calibration model was provided. In order to obtain different gray-scale data, two-dimensional scanning of different gray-scale target plates was carried out by using ground laser scanner. The accuracy of different distance calibration models was compared by using different distance data. The experimental results show that accuracy of the gray-scale priority calibration model is higher than the precision of the constant priority calibration model, and the distance accuracy is improved to 5 mm. At the same time, the result of the gray-scale priority calibration model is not affected by the gray scale and has universality.