A pixel structure of an electroluminescent display panel includes a first sub-pixel region, a second sub-pixel region, a third sub-pixel region and a fourth sub-pixel region having different cavity lengths. The first sub-pixel region and the second sub-pixel region share a first organic light-emitting layer, which can generate a first primary color light in the first sub-pixel region, and a second primary color light in the second sub-pixel region. The third sub-pixel region and the fourth sub-pixel region share a second organic light-emitting layer, which can generate a third primary color light in the third sub-pixel region, and a fourth primary color light in the fourth sub-pixel region. The first primary color light, the second primary color light, the third primary color light and the fourth primary color light have different spectra of wavelength.