Abstract: The invention relates to a driving method for thin film transistor liquid crystal display (TFT-LCD) by applying AC or DC signals on the common electrode of the storage capacitor of each of the pixel of the TFT substrate or on the opposite electrode of the liquid crystal during video-blanking periods. The applied AC or DC signals generate a pre-added voltage on the liquid crystal of each of the pixel. Since the optical performance of liquid crystal molecules depends on the root-mean-square value of the total induced voltage, the voltage for driving all of the pixels is decreased by using the pre-added voltage applied at each of the pixel. In particular, the threshold value of driving voltage is considerably decreased, thereby, a data driver IC with lower voltage is employed so as to lower the cost.