An organic light emitting diode (OLED) display device includes a communication transceiver configured to connect with a terminal; a display including pixels constituted by OLEDs; and a controller configured to receive mirroring image data, which corresponds to a screen displayed on the terminal, through the communication transceiver, control the display to display a mirroring image on an area of the display based on the received mirroring image data, and adjust brightness of the displayed mirroring image based on an average picture level (APL) of the displayed mirroring image.