An organic light emitting display substrate includes: a base substrate; organic light emitting diodes disposed on the base substrate, with each organic light emitting diode including a first electrode layer, an organic light emitting layer and a second electrode layer, and the first electrode layer and the second electrode layer forming an optical resonant cavity; and a nanoparticle layer on a side of the organic light emitting diodes away from the base substrate and includes nanoparticle patterns, each nanoparticle pattern is disposed on a side of a second electrode layer of a corresponding one of the plurality of organic light emitting diodes away from an organic light emitting layer and at least partially covers the second electrode layer. Resonance mode of the nanoparticle pattern is coupled with a resonance mode of an optical resonant cavity of the corresponding organic light emitting diode to form a Fano resonance.