The characteristics including intrinsic property of a‐Si ‐TFT and LTPS TFT for the application used as OLED backplane are reviewed. Though a‐Si AMOLED shows better uniformity and is capable of driving OLED, the stability of a‐Si TFT under operation is still not acceptable, while LTPS TFT reveals satisfactory stability in AMOLED application. The stability of TFT under long‐term operation is remained to be the key issue for commercialization of a‐Si TFT AMOLED.