An organic light-emitting display device and a manufacturing method thereof are provided by the embodiments of the present disclosure, and the organic light-emitting display device includes: a substrate; a plurality of pixel definition strips disposed on the substrate, in which the plurality of pixel definition strips are spaced apart from and arranged in parallel with each other, and two adjacent pixel definition strips among the plurality of pixel definition strips and a portion of the substrate between the two adjacent pixel definition strips constitute a pixel definition groove; and an organic light-emitting functional layer disposed in the pixel definition groove, the organic light-emitting functional layer includes a plurality of sub organic light-emitting functional layers which are insulated with each other and arranged along an extension direction of the plurality of pixel definition strips.