The invention discloses a method and an apparatus for generating a disparity map based on image frames photographed by a stereo camera. The method includes steps of generating an initial standard grayscale histogram and an initial reference grayscale histogram based on a first image frame, generating a target standard grayscale histogram and a target reference grayscale histogram for a predetermined area of a first standard image based on historical information of a second image frame, calculating a standard mapping function from the initial standard grayscale histogram to the target standard grayscale histogram and a reference mapping function from the initial reference grayscale histogram to the target reference grayscale histogram, performing the standard mapping function on the predetermined area of the first standard image to obtain an enhanced standard image of the first image frame and performing the reference mapping function on the predetermined area of the first reference image to obtain an enhanced reference image of the first image frame, and generating a first disparity map corresponding to the first image frame based on the enhanced standard image and the enhanced reference image of the first image frame.