The effects of copper phthalocyanine (CuPc)/4,4('),4(')-tris(3-methylphenylphenylamino)triphenylamine (m-MTDATA) double buffer layers structure on the electrical and optical characteristics of white organic light-emitting diodes (OLEDs) were systematically investigated. The CuPc layer was suggested to enhance hole injection, and the m-MTDATA layer transport holes into the emission zone by means of the formation of a stepped energy level. The CuPc/m-MTDATA double buffer layer structure has successfully decreased the driving voltage. Furthermore, the luminous efficiency is about 1.6 and 1.3 times the values for white OLEDs in which a single m-MTDATA and CuPc, respectively, are used as a buffer layer. Evidence indicates that inserting double buffer layers of CuPc/m-MTDATA improved considerably the electrical and optical characteristics of white OLEDs.