The invention relates to a liquid crystal display device. A bottom layer common electrode, a first insulating layer, a first metal layer, a second insulating layer, an amorphous silicon layer, a second metal layer, a third insulating layer and a pixel electrode (6) are arranged sequentially from glass of a first substrate to a liquid crystal layer of the first substrate. The bottom layer common electrode is a planar common electrode (1) and is integrally arranged on the glass of the first substrate. In the invention, an overlapping area between the pixel electrode and the common electrode is increased; an adjustable range of a pixel storage capacitance value is improved; a linear metal common electrode line is changed into the planar common electrode made of transparent materials, so thatthe power supply capacity of the common electrode is improved and the potential uniformity at different positions of the common electrode is improved; and by combining light shading lines at both ends of a data line, the pixel aperture opening ratio is improved and a coupling capacitor between the data line and the bottom layer common electrode is reduced. The bottom layer common electrode only needs to be subjected to a sputtering film forming process and does not need to be subjected to a photolithographic process by a special mask plate, so that the production cost is effectively reduced and the economic benefits are improved.