A method for adjusting a gamma voltage of an OLED display device, including; acquiring a test picture pre-stored in the OLED display device, and extracting a first piece of data information on the test picture; comparing the first piece of data information with a pre-stored second piece of data information on the test picture before the OLED display device is aged, analyzing a comparison result, and obtaining the aging coefficient of the OLED display device; acquiring a set of gamma voltage values corresponding to the aging coefficient, outputting the set of gamma voltage values to a gamma integrated circuit of the OLED display device, and completing the adjustment of the gamma voltage.