The invention provides a lane line detection method, a lane line detection device and a terminal, which relate to the technical field of image processing. The lane line detection method comprises thesteps of: filtering a to-be-detected image by means of a preset filtering template to obtain a filtered image, wherein weight parameters on a diagonal of the preset filtering template are greater thanweight parameters on an off-diagonal in a neighborhood; determining an edge binarized image of the filtered image; determining gradient directions of white pixel points in the edge binarized image, and determining the white pixel points with the gradient directions satisfying set conditions to be effective pixel points; and performing Hough line detection on all the effective pixel points to obtain a lane line in the to-be-detected image. By applying the lane line detection method, the subsequent lane line detection efficiency according to the white pixel points can be improved.