A TFT array substrate structure includes a patterned metal light-shielding layer that includes a plurality of metal light-shielding blocks arranged in an array and a narrowed metal strip connected between two adjacent ones of the metal light-shielding blocks. The metal light-shielding layer and a common electrode are connected to and receive a common voltage signal. For each of TFT, the pixel electrode is connected to a drain electrode of the TFT; the pixel electrode has a portion overlapping the common electrode to form a first storage capacitor; and the metal light-shielding layer has a portion overlapping the drain electrode and the pixel electrode to form a second storage capacitor. The first storage capacitor and the second storage capacitor are connected in parallel to increase the capacity of the storage capacitor. The metal light-shielding layer is arranged in a light-shielded area and thus the modification thereof does not affect aperture ratio.