A thin film transistor array substrate and a display apparatus are disclosed. The thin film transistor array substrate includes a number of scan lines, data lines and pixel units. Each of the pixel units includes a thin film transistor and a pixel electrode. The thin film transistor includes a gate electrode, a source electrode and a drain electrode. The gate electrode is electrically connected to one of the scan lines, the source electrode is electrically connected to one of the data lines, and the drain electrode is electrically connected to the pixel electrode. The source electrode is arranged in a same layer as the data lines while the drain electrode and the source electrode are respectively arranged in different layers. Therefore, the implementation of the present disclosure may augment the PPI (Pixel units per Inch) of display apparatus without reducing its aperture ratio and product yield ratio.