Based on the density functional theory (DFT) and time-dependent (TD) DFT methods, the geometric and spectroscopic features of (CuSe)n = 2–8 binary nanoclusters were systematically studied, and five kinds of isomers are obtained as local minima structures at each cluster size. The BHandH hybrid functional and effective core potential basis set LanL2DZ are used for copper atoms. The triple-ζ valence plus polarization basis set TZVP is selected for selenium atoms. For each cluster size, the relative energies of these five stable isomers are evaluated for the conformational isomerization. There are significant differences in infrared spectra between the isomeric structures, and the infrared spectra bands distinctly show differences in the low-frequency region between smaller size clusters and higher size clusters. The higher molar absorption coefficient is consistent with UV-Vis spectroscopy in the wavelength range of 200~400 nm. The calculated UV-Vis spectra clearly show that all clusters exhibit permissible excited electronic transitions in the range 0~10 eV. Therefore, these clusters can be used as potential UV-absorbing materials due to their strong UV absorption.