Abstract: Nano-composite mesostructured thin films containing rhodamine B have been prepared.A precursor sol containing tetraethoxysilane,ethanol,surfactant cetyltrimethylammonium bromide（CTAB）,water,rhodamine B and acid catalyst was prepared by sol-gel,the control being suitable response condition.Depositing the precursor sol on a substrate wherein evaporation of solvent and water causes the formation of mesostructured films on the substrate surface by evaporation-induced self-assembly process.The mesoporous film was characterized by XRD and TEM.The absorption and fluorescence spectra of the films have been observed.The UV-visible absorption spectra of the films incorporated with rhodamine B show that the main absorption band of rhodamine B-doped films can be attributed to the rhodamine B monomers,and only a very weak absorption band of the dimer can be observed.The single emission band in fluorescence spectra of rhodamine B-doped films can be attributed to transitions from the lowest-lying level of the first excited electronic state to the electronic ground state of rhodamine B monomers.The red shifts in the peak of the luminescence spectra with increasing rhodamine B-content in the films which may be interpreted as reflecting a decrease in the dipole moment of the excited molecule.