Embodiments of the invention provide a manufacturing method of a TFT array substrate. The TFT array substrate is formed to comprise a plurality of scanning lines, a plurality of data lines and a plurality of pixel units defined by intersecting these scanning lines and these data lines with each other. Each of the pixel units comprises a TFT and a pixel electrode. The TFT is formed to comprise a gate electrode, a gate insulating layer, a metal oxide semiconductor layer used as an active layer, an etch stopping layer formed on a portion of the surface of the metal oxide semiconductor layer, a source electrode and a drain electrode. In this method, the metal oxide semiconductor layer, the source electrode and the drain electrode are formed by a same patterning process.