The disclosure discloses a road region detection method and device and a terminal, and relates to the field of aided-driving technology. A scheme includes: acquiring a parallax image containing a roadregion, and generating a first V-disparity map corresponding to the parallax image; carrying out straight-line detection in the first V-disparity map, and forming a straight-line extension region, which represents the road region, around a detected straight line; generating a U-disparity map, which corresponds to first parallax points obtained by mapping of the straight-line extension region in the parallax image, according to the first parallax points; carrying out straight-line detection in the U-disparity map, forming straight-line extension regions around straight lines detected in the U-disparity map, and obtaining second parallax points by mapping of the straight-line extension regions in the parallax image; and obtaining intersection points of the first parallax points and the second parallax points in the parallax image by screening to obtain road fitting points representing the road region in the parallax image. According to the method, joint constraint is carried out throughthe V-disparity map and the U-disparity map, the road parallax points can be accurately found, and thus accurate detection of the road region is realized.