A thin film transistor array substrate includes a bottom gate disposed on a substrate and a bottom gate insulating layer covering the bottom gate, a semiconductor oxide layer disposed on the bottom gate insulating layer and an etch blocking layer covering the semiconductor oxide layer and including a first via, a drain disposed on the etch blocking layer and contacting with the semiconductor oxide layer through the first via and an insulating protection layer covering the drain, a second via arranged in the insulating protection layer, the etch blocking layer and the bottom gate insulating layer, a top gate disposed on insulating protection layer and contacting with the bottom gate through the second via. A method for manufacturing the thin film transistor array substrate is also disclosed. The thin film transistor prevents the threshold voltage thereof from being drifted in a case of negative bias illumination stress (NBIS).