A method of preparing organic functional layers of light-emitting device including: forming a plurality of holding portions in a pixel definition layer on a substrate; forming a plurality of ink droplets in the holding portions, the ink droplets including a first solvent, a second solvent and one or more solutes, a first saturated vapor pressure of the first solvent being higher than a second saturated vapor pressure of the second solvent, a solubility of the solutes in the first solvent being less than a solubility of the solutes in the second solvent, and a first affinity of lower parts of side walls of the holding portions for the first solvent is greater than a second affinity of the lower parts of the side walls of the holding portions for the second solvent; adjusting a vacuum degree of vacuum drying equipment to a first vacuum degree below the first saturated vapor pressure and above the second saturated vapor pressure to completely remove the first solvent; and adjusting the vacuum degree of the vacuum drying equipment to a second vacuum degree below the saturated vapor pressure of the second solvent to completely remove the second solvent.