The present invention relates to the field of liquid crystal display technology and provides an array substrate and a liquid crystal display device which can solve the problem of low transmissivity of existing liquid crystal display devices. The array substrate of the present invention comprises a plurality of pixel units, each pixel unit is provided with a plate electrode and a slit electrode arranged above the plate electrode, an insulation layer is provided between the plate electrode and the slit electrode, and the plate electrode extends to the periphery region of the pixel unit, the slit electrode extends to the periphery region of the pixel unit; the slit electrode and the plate electrode are both provided in at least part of the peripheral region of the pixel unit. the present invention is applicable to liquid crystal display devices, especially the liquid crystal display devices taking a “dual gate lines” design.