The present disclosure proposes an OLED display device, a manufacturing method thereof and an OLED Display. The OLED display device includes a substrate and a color conversion layer and a blue-green light emitting layer disposed in a stack on the substrate. The color conversion layer includes blue filter units, green conversion units and red conversion units disposed apart from one another. Both the green conversion units and the red conversion units are film layers made of an organic metal halide perovskite material. The green conversion units and the red conversion units respectively absorb blue-green light emitted from the blue-green light emitting layer, and convert the blue-green light into green light and red light, the blue filter units filter the blue-green light to obtain blue light so as to achieve color display.