The invention discloses an array substrate and a manufacturing method thereof, a liquid crystal display panel, and a display device. The array substrate comprises a base substrate, a data line arranged on the base substrate, and a pixel electrode layer which is arranged above the layer where the data line is positioned, and is formed by a plurality of pixel electrodes, wherein the orthographic projection, formed on the base substrate, of the data line covers the orthographic projection, formed on the base substrate, of a gap between two adjacent columns of pixel electrodes, and the width of the data line is larger than that of the gap between two adjacent columns of pixel electrodes. The orthographic projection, formed on the base substrate, of the data line covers the orthographic projection, formed on the base substrate, of the gap between two adjacent columns of pixel electrodes, and the width of the data line is larger than that of the gap between two adjacent columns of pixel electrodes, so that a longitudinal electric field line from the array substrate to an opposite substrate is formed between the data line and the pixel electrodes; therefore, the light leakage along the direction of the data line is prevented by controlling liquid crystal torsion; furthermore, a black matrix is avoided being used for preventing the light leakage, so that aperture opening ratio is effectively increased.