The invention discloses a thin film transistor array substrate and a liquid crystal display device. The thin film transistor array substrate comprises a first electrode, a first insulation layer and a second electrode, all of which are arranged on a substrate. The second electrode is located above the first electrode. The first insulation layer is clamped between the first electrode and the second electrode. The first electrode is of a planar structure. The second electrode is of a stripped structure and comprises multiple electrode strips which are mutually spaced. The second electrode is provided with a second insulation layer. The second insulation layer comprises multiple insulation strips which are mutually spaced. The multiple insulation strips are arranged on the multiple electrode strips in a one-to-one correspondence mode. Each insulation strip extends along the length direction of a corresponding electrode strip. By making a layer of insulation and protection layer above the second electrode, a vertical electric field above the second electrode is undermined. The standing angle of positive dielectric anisotropy above the second electrode is reduced when an FFS-type liquid crystal display device displays. Therefore, light transmissivity of positive dielectric anisotropy is improved.