The present disclosure discloses a method for manufacturing a TFT array substrate, comprising: depositing a gate metal layer, a gate insulating layer, a semiconductor layer and a source-drain electrode layer in this order on a base substrate, performing a first photolithograph process to form a common electrode line, a gate line, a gate electrode, a source electrode, a drain electrode and a channel defined between the source electrode and the drain electrode; depositing a passivation layer, performing a second photolithograph process to form a first via hole and a second via hole in the passivation layer; and depositing a pixel electrode layer and a data line layer in this order, perform a third photolithograph process to form a data line connected to the source electrode through the first via hole and a pixel electrode connected to the drain electrode through the second via hole.