Silver nanoparticles (Ag NPs) were prepared by using the reducing agent trisodium citrate with the precursor AgNO3 and stabilized by ascorbic acid. The increase in concentrations of AgNO3 significantly changes the color from light brown to dark brown. This color change indicates the formation of silver nanoparticles. The re sulting AgNPs were characterized by UV-VIS and FTIR techniques. In this study, the effects of concentrations of AgNO3 on the bandgap energy, absorption, reflection and transmission of the silver nanoparticles were investigated. It was found that the increasing concentration of silver nitrate resulted in an increasing absorption of silver nanoparticles, but its absorption peak observed at the same wavelength, 416nm. The optical direct band gap energy was decreased from 3.52eV to 3.36eV as silver nitrate concentration increased from 0.1M to 0.6M. The optical direct band gap of silver nanoparticles calculated by the tauc plot model, which indicates band gap of syn thesized silver nanoparticles more than bandgap energy of bulk silver. This higher value of band gap might be due to a decrease overlapping of energy levels depend on its small number of atoms. Finally, from the FTIR measurements, we have ob served that the transmission of infrared decreases as concentration increases. But the molecular vibration of the AgNPs show the same functional group with the same wave number. molecular vibration of the silver nanoparticles showed high coherency at different concentrations. Keywords: Silver nanoparticles, Chemical reduction method, UV-Vis absorption, Molecular band of FTIR.