The present application discloses an array substrate and a display panel. The array substrate includes a plurality of pixel units arranged in an array, each of the pixel units includes a thin film transistor. The thin film transistor includes a gate electrode and a drain electrode. A first overlap region and a non-overlap region is defined between the gate electrode and the drain electrode. The first overlap region is adjacent to the non-overlap region. A width of a cross section of the drain electrode in the first overlap region is less than a width of a cross section of the drain electrode in the non-overlap region. The array substrate can reduce a parasitic capacitor between the gate electrode and drain electrode.