The disclosure provides a method of manufacturing a display panel and a method of manufacturing a functional layer thereof. The method of manufacturing the functional layer includes following steps: forming an ink layer on a display area of a substrate by inkjet printing, wherein the ink layer includes a solute and a solvent configured to dissolve the solute, different positions of the ink layer have same amount of the solute, and an amount of the solvent in a periphery of the ink layer is greater than an amount of the solvent in a middle portion of the ink layer; and evaporating the solvent in the ink layer to form the functional layer with uniform thickness.