An organic light-emitting diode (OLED) display device and an operating method thereof are disclosed. The OLED display device includes an OLED panel, a non-volatile memory and a volatile memory. The non-volatile memory is coupled to the OLED panel and used for storing accumulated current data from the OLED panel. The volatile memory is coupled between the non-volatile memory and the OLED panel and used for storing a compensation value generated according to the accumulated current data stored in the non-volatile memory. When the OLED panel is directly compensated with the compensation value, the non-volatile memory receives and stores updated accumulated current data of the OLED panel.