The invention provides a thin film transistor array substrate, a preparation method thereof and a liquid crystal display panel. The array substrate comprises an array substrate supporting base, a thin film transistor array layer arranged on the array substrate supporting base, a color filter layer arranged on the thin film transistor array layer and the array substrate supporting base, a pixel electrode passivation layer arranged on the color filter layer and a pixel electrode arranged on the pixel electrode passivation layer, wherein the pixel electrode is connected with the thin film transistor array layer through a via hole, and graphical sunk microstructures are formed on the surface of the color filter layer. The thin film transistor array substrate, the preparation method thereof and the liquid crystal display panel have the advantages as follows: on the premise that the manufacturing cost is not increased, the graphical sunk microstructures are formed on the surface of the color filter layer by the aid of a photomask for forming the via hole, so that volatile matter produced in a color resistance manufacturing process and a follow-up high-temperature manufacturing process of the pixel electrode passivation layer is totally released, gas residues are avoided, the probability of bubbles produced by a product in a later period is eliminated, and the quality of the product is improved.