Abstract: In order to meet the requirements of uniform lighting in visibility meter using the digital camera method and improve the uniformity of LED lighting, a design method based on digital image analysis technique was presented. Firstly,according to the measurement of the brightness distribution of a single LED in the module area, the distribution function was fitted. Then by using the principle of brightness superposition, the arrangement of the multi-LED module with the lowest inhomogeneity or the best size of a fixed uniform was calculated. Furthermore,the simulated data and the measured data were comparative analyzed. Experimental results show that the uniformity is improved significantly in the arrangement of multi-LED module proposed in this paper, compared with in unilateral arrangement. The highest uniformity is above 95%.