The disclosure relates to a method of making organic light emitting diode array. A base defining a plurality of convexities is provided. A number of first electrodes are applied on the plurality of convexities. A number of red light electroluminescent layers are transfer printed on a first group of the first electrodes. A number of green light electroluminescent layers are transfer printed on a second group of the first electrodes. A number of blue light electroluminescent layers are transfer printed on a third group of the first electrodes. A patterned second insulative layer is made to cover the number of first electrodes and expose the electroluminescent layers. A second electrode is electrically connected to the electroluminescent layers.