The present disclosure describes methods, device, and storage medium for obtaining lane line data of a road. The method includes obtaining and dividing, by a device, road-image data of a road into at least one segment. The device includes a memory storing instructions and a processor in communication with the memory. The method includes processing, by the device, each segment to obtain a two-dimensional grayscale image of each segment; extracting, by the device using a pre-trained deep neural network model, a lane line area and a lane line attribute in each two-dimensional grayscale image, to obtain a lane line area image of each segment; and splicing, by the device, each lane line area image based on corresponding road-image data and the lane line attribute, to obtain lane line data of the road.