A display device including a timing control circuit, a programmable voltage generator, a gate driver, a source driver circuit and a display panel is provided. The display panel includes a plurality of redundancy pixel cells and display pixel cells. The redundancy pixel cells and display pixel cells may include a--Si TFT and organic light emitting diode. The redundancy pixel cells and display pixel cells may be turned on by the gate driver circuit, and the working current of each display pixel cell may be compared with that of the corresponding redundancy pixel cell. Then timing control circuit may control the programmable voltage generator to generate applicable voltage of data to the source driver circuit to compensate the shift of the working current of the display pixel cells after working a period of time according to the comparison result.