Different substituents result in different changes in electron-photon spectra, and to reveal the relationship between substituents and spectra, a theoretical investigation was elaborated via quantum chemical calculations. Density functional theory and single excitation configuration interaction were respectively employed in optimizing geometric and electronic structures of ground and excited states, and the absorption and emission spectra were studied by time-dependent density functional theory methods. The results show that all the different substituents bring on different geometric and electronic structures of ground and excited states, different energies of frontier molecular orbitals as well as different π-conjugated systems, the spectra change with all the differences，and relationships are brought out in this paper, which gives theoretical reference for identifying different derivatives from electron-photon spectra.