Novel near-infrared (NIR) light-emitting devices with a structure of PbS quantum dots (QDs)/glass/indium-tin oxide (ITO)/poly (N-vinylcarbazole) (PVK) :N,N ′-bis(naphthalen-1-y)-N,N′-bis(phenyl) benzidine (NPB)/Al are fabricated. A hybrid system consisting of small molecular blue fluorescent material of NPB a nd polymer material of PVK is employed as the blue light emitting layer,and the near-infrared wavelength convers ion film is prepared by dispersing PbS quantum dots into the mixture of the A,B epoxy resin.The blue light emitti ng layer has a emission around 445nm,and the emission comes from the NPB.With various size of PbS quantum dots which were synthesized with different precursor molars of S/Pb,the EL spectrum shows tunable emission peaks at 900-1600nm in the near-infrared range under forward bias.The NIR emission intensity is improved by optimizing the ratio of PbS quantum dots in the wavelength conversion film.The increased ratio of PbS quant um dots can enhance the probability of blue light absorption.When the ratio reaches 10%,the emission int ensity tends to be the highest.