The invention provides an array substrate and a manufacturing method thereof. The array substrate comprises a substrate body, a first metal layer arranged on the substrate body, a first insulating layer covering the first metal layer and the substrate body, a second metal layer arranged on the first insulating layer, a passivation layer covering the first insulating layer and the second metal layer, and a pixel electrode arranged on the passivation layer. The first metal layer comprises a first electrode plate, the second metal layer comprises a second electrode plate opposite to the first electrode plate and an array substrate common electrode wire electrically connected with the second electrode plate, and a part of the pixel electrode is located above the second electrode plate; the pixel electrode is electrically connected with the first electrode plate through a first through hole running through the passivation layer and the first insulating layer; the first electrode plate, thesecond electrode plate and the pixel electrode form an interlayer capacitor, the area of a storage capacitor in the same size can be reduced, and the aperture rate is increased.