Mesoporous AlPO4 glass with high surface area is prepared with new sol-gel processing, followed by incorporating coumarin 102 with dipping method. The effects of coumarin 102 concentration on the optical properties of AlPO4 glass and molecular formation of coumarin 102 are studied by excitation spectra and emission spectra methods. The main excitation band placed at 366 nm is ascribed to monomeric coumarin 102 in excitation spectra, and the main excitation band is broadened due to the aggregating of fluorescent dimers in the mesoporous glass as coumarin 102 concentration increases from 5×10-6 mol/L to 5×10-3 mol/L. Red shift of emission band from 459 nm to 479 nm is observed in emission spectra as coumarin 102 concentration increases from 5×10-6 mol/L to 5×10-3 mol/L. The tunable width is 135 nm when the concentration is 5×10-3 mol/L. The stability of the coumarin 102 absorbed in the AlPO4 mesoporous glass is investigated by bleaching experiment.