1. An image stitching method, comprising: obtaining two images between which an overlap region exists; searching for the overlap region of the two images; obtaining a depth image of the overlap region; and stitching the two images into one image according to the depth image, wherein the stitching of the two images into one image according to the depth image comprising: calculating a homographic matrix between the two images; mapping a first image to a target coordinate system according to a mapping relation between the first image and the homographic matrix; calculating an amount of parallax between corresponding pixels of the two images in the overlap region according to the depth image; discarding pixel points of a second image if the parallax amount falls within a preset parallax range; mapping pixel points of the second image in the overlap region to coordinates of corresponding pixel points of the first image in the target coordinate system if the parallax amount exceeds the preset parallax range; and mapping pixels of the second image outside the overlap region to the target coordinate system according to a mapping relation between the second image and the homographic matrix.