The application provides an OLED device, a manufacturing method thereof, and a display device, which reduce or eliminate color cast in an image displayed by an existing OLED device due to different lifetimes of organic materials for light emitting layers emitting light of different colors in the OLED device. In the OLED device, a luminous efficiency regulator is disposed between a cathode and a light emitting layer of at least one sub-pixel, and a vibration characteristic peak of the luminous efficiency regulator falls within a wavelength range of light emitted from the corresponding light emitting layer, such that attenuation rates of lighting luminance of the light emitting layers emitting light of different colors are kept consistent with each other over time.