The present disclosure provides an OLED display device and its manufacturing method. The OLED display device includes an organic light-emitting layer and a plurality of elements arranged one on another at a light-exiting side of the organic light-emitting layer. At least one transparent light extraction layer is arranged between the elements, and/or between the organic light-emitting layer and the element adjacent to the organic light-emitting layer, and/or at a light-exiting surface of the element farthest away from the organic light-emitting layer. A refractive index of the organic light-emitting layer and/or a refractive index of the element adjacent to the light extraction layer, and a refractive index of the light extraction layer decrease successively in a light emergent direction, and the refractive index of the light extraction layer is greater than a refractive index of air.