A thin film transistor array substrate having excellent characteristics and a method for manufacturing the same are disclosed. The thin film transistor array substrate includes a substrate, a gate electrode positioned on the substrate, a gate insulating layer positioned on the gate electrode, an active layer which is positioned on the gate insulating layer and includes a channel, an ohmic contact layer positioned on the active layer, and a source electrode and a drain electrode which are respectively connected to both sides of the active layer through the ohmic contact layer. The gate insulating layer includes a phosphorus-doped layer positioned adjacent to the active layer.