The present invention relates to a module and method for detecting a defect of a thin film transistor (TFT) substrate, which can detect disconnection of a gate line of the TFT substrate having gate drivers provided with a dual structure in which the gate drivers are provided at both sides of the gate lines. There is provided a module and method for detecting a defect of a TFT substrate, wherein gate lines are separated into two portions by cutting a central region of the gate lines, gate power is supplied to the gate lines of which central portions are cut through gate drivers provided at both sides of the gate lines, and a signal of a negative voltage level is supplied to data lines, so that disconnection of the gate lines can be detected.