The invention relates to the field of display device technology, more particularly, to an organic light-emitting diode device and a manufacturing method thereof and an organic light-emitting display panel, which changes the traditional micro-cavity structure, spin-coatings the liquid filling agent on the cathode layer to form the micro-cavity adjusting layer, and make it between the cover and the cathode layer, on the one hand, controls the thickness of the filling agent by spin-coating to change the resonance node of OLED, to achieve the strongest resonance effect, and at the same time avoid the defect of high cost of traditional evaporation; on the other hand, configuring the micro-cavity adjusting layer on the cathode layer, when OLED in working state, the length of the electric current passing through significantly shortens, the resistance reduces, and effectively reduces the working voltage of OLED device and improves the emitting efficiency of OLED device.