Effects of metallic ions, such as Zn2+, Mn2+, Cd2+, Na+, K+, Ag+, Cu2+ and Pb2+, on the photoluminescence properties of ZnS(ZINC sulfide) QDs (quantum dots)/poly(amido amine)(PAMAM) dendrimer nanocomposites(NCs) with blue emission under the irradiation of UV light were studied. The results show that the effects of different metallic ions on the photoluminescence properties of the prepared ZnS QDs were different. Zn2+, Mn2+ and Cd2+ ions enhance the PL(photoluminescence) intensity; Na+ and K+ ions don’t change the PL intensity obviously while Ag+, Cu2+ and Pb2+ quench it. Compared with ZnS/PAMAM NCs, fingerprints treated with ZnxCd(1-x)S/PAMAM NCs emitted brighter blue light, the contrast between abstracts and fingerprints was more obvious, which shows good reference value for enhancing the resolving ability of fingerprints.