An auto white balance adjusting method includes acquiring an image, allocating N windows inside the image according to color information of the image, filtering out M windows from the N windows for generating N-M windows according to feature information of the N windows, grouping the color temperatures of the N-M windows for generating at least one color temperature group according to a standard color temperature curve, setting a first weighting of the at least one color temperature group according to a correlation between the at least one color temperature group and the standard color temperature curve, setting a second weighting of the at least one color temperature group according to spatial information of the at least one color temperature group of the image, and adjusting a white balance of the image according to color information, the first weighting, and the second weighting.