Provided is a method of manufacturing TFT substrate, the method including: forming a first conductive layer and a gate electrode; forming a gate insulating layer covering the first conductive layer and the gate electrode; forming a first contact hole exposing the first conductive layer through the gate insulating layer; forming, on the gate insulating layer of a pixel area, an oxide semiconductor pattern comprising a first region which is conductive, a second region which is conductive, and a third region between the first region and the second region; forming a source electrode contacting the first region of the oxide semiconductor pattern, a drain electrode contacting the second region of the oxide semiconductor pattern and a second conductive layer contacting the first conductive layer on a non-pixel area. Each of the first region and the second region overlaps the gate electrode.