A brightness adjustment method for multi-camera mosaicing, which comprises steps of: acquiring six original images respectively photographed by six cameras and expanding the six original images into latitude and longitude images to acquire corresponding six groups of overlapping region images thereof wherein the six groups of overlapping region images are pairs of overlapping region images marked as sl[i] and rl[i], i=1-6, where sl[i] and rl[i] are a pair of overlapping region images, sl[i] is photographed by the i camera, when i=1~5, rl[i] is photographed by the i+1 camera, when i=6, rl is photographed by the first camera; characterized in that the method further comprises the steps of mapping the original image photographed by each camera with a respective brightness mapping function, and calculating a sum of the brightness differences of the six groups of overlapping region images as a total brightness error; adjusting the brightness mapping function of each camera respectively to minimize the total brightness error to obtain an optimal brightness mapping function for each camera; keeping an image with a dark part being the brightest in the original images unchanged, finding the brightness mapping function of the image with a dark part being the brightest, calculating its inverse function to provide a first adjustment function, adjusting the optimal brightness mapping function for each camera with the first adjustment function and mapping all the original images for panoramic mosaicing to generate a dark panoramic mosaic image, and keeping an image with a bright part being the darkest in the original images unchanged, finding the brightness mapping function of the image with a bright part being the darkest, calculating its inverse function to provide a second adjustment function, adjusting the optimal brightness mapping function for each camera with the second adjustment function and mapping all the original images for panoramic mosaicing to generate a bright panoramic mosaic image; and fusing the dark panoramic mosaic image and the bright panoramic mosaic image to generate a panoramic mosaic image. acquiring six original images respectively photographed by six cameras and expanding the six original images into latitude and longitude images to acquire corresponding six groups of overlapping region images thereof wherein the six groups of overlapping region images are pairs of overlapping region images marked as sl[i] and rl[i], i=1-6, where sl[i] and rl[i] are a pair of overlapping region images, sl[i] is photographed by the i camera, when i=1~5, rl[i] is photographed by the i+1 camera, when i=6, rl is photographed by the first camera; characterized in that the method further comprises the steps of mapping the original image photographed by each camera with a respective brightness mapping function, and calculating a sum of the brightness differences of the six groups of overlapping region images as a total brightness error; adjusting the brightness mapping function of each camera respectively to minimize the total brightness error to obtain an optimal brightness mapping function for each camera; keeping an image with a dark part being the brightest in the original images unchanged, finding the brightness mapping function of the image with a dark part being the brightest, calculating its inverse function to provide a first adjustment function, adjusting the optimal brightness mapping function for each camera with the first adjustment function and mapping all the original images for panoramic mosaicing to generate a dark panoramic mosaic image, and keeping an image with a bright part being the darkest in the original images unchanged, finding the brightness mapping function of the image with a bright part being the darkest, calculating its inverse function to provide a second adjustment function, adjusting the optimal brightness mapping function for each camera with the second adjustment function and mapping all the original images for panoramic mosaicing to generate a bright panoramic mosaic image; and fusing the dark panoramic mosaic image and the bright panoramic mosaic image to generate a panoramic mosaic image.