Disclosed are OLED display panel and method for manufacturing the same, as well as display device including the OLED display panel. The present disclosure belongs to the field of an organic light emitting diode. The OLED display panel includes a light emitting structure, a TFT backplane, and an insulating layer. The insulating layer locates between the light emitting structure and the TFT backplane. A refractive index of the insulating layer gradually decreases in a direction of an emergent ray of the light emitting structure. The technical solution of the present disclosure may decrease influences of the emergent ray of the light emitting structure on TFT performance.