Two kinds of organic-inorganic comp osite luminescent material were pre pared through sol-gel route,by dopi ng o-amino-benzoic acid(ABA)or N-phenylanthranilic acid(N-PA)into SiO 2 xerogels.Fluorescence properties and thermal properties of ABA and N-PA in SiO 2 xerogels were studied.The relation ship between the fluorescence properties and the preparative cond ition was also studied.The results s howed that the ABA was easy to form dim er of non-luminescence among the molec ules.The quenching concentration o f the ABA was obviously increased owi ng to the shield of silica network.The f luorescence intensity of the composite material prepared at the acid con dition was decreased,and a red shift for the fluorescence peak appeared.With th e increasing of the pH value,the flu-orescence peak blue shifted and the i ntensity was increased.However,th e fluorescent intensity of N-PA /SiO 2 was increasing due to the concentration of N-PA was increased.The thermal stability of ABA and N-PA in the composite material was also improved.But,when the temperature continued to incre ase,the collapse of the silica netwo rk made the organic molecules escape fr om the pore of the silica network,the decomposition of escaping molecule s decreased the intensity of emission spectrum.