Disclosed is a panoramic image mapping method, wherein mapping regions and a non-mapping region are partitioned for an equirectangular panoramic image with a resolution of 2M×M, where only the partitioned mapping regions are mapped as square regions; the method comprises:, computing a vertical distance and a horizontal distance from a point on the square region to a center of the square region, a larger one of which being denoted as m; computing a distance n from the point to a zeroth (0th) point on a concentric square region; computing a longitude and a latitude corresponding to the point; computing a corresponding position (X, Y) in the equirectangular panoramic image to which the point is mapped; and then assigning a value to the point. The method may effectively reduce oversampling, thereby effectively reducing the number of pixels of the panoramic image and the code rate required for coding with little distortion.