The invention relates to an organic light-emitting diode (OLED) display device and a manufacturing method thereof. In the invention, a first retaining wall corresponding to a bending region is configured to include first retaining wall units spaced apart from each other, and a first buffer structure is formed in a gap provided between the first retaining wall units and is alternately connected to a left side and a right side of the first retaining wall units. This can prevent excessive stress concentration on the retaining wall in the bending region due to its special configuration, which causes a phenomenon of film layer detachment. Therefore, a failure of the OLED display device is prevented.