Abstract: Triphenyl diamine(TPD) was investigated as a charge transport agent and a light emitting material in electroluminescence.Davydov splitting was observed in the TPD thin film prepared by vacuum deposition.The surface morphology of TPD thin films before and after annealing were compared by AFM.Blue light emission was determined in TPD single layer EL device after annealing.The action of charge transport of TPD in double layers EL device were analysised and the intensification of electron-hole composite at the interface of double layes was confirmed.