Silica gels have lots of unique capabilities. In this paper organic dyes doped silica gels were prepared by sol-gel method in order to find the effect of the catalysts on structure and optical properties of the composite. From the emission spectra of coumarin 102(C102) in different conditions

the emission peak of PL shifted to short wavelength in both the composite material films compared with solution. Most of dye molecules were being monomers in ethanol

and few of them were being dimmer. As water joined it was found that a red-shift of emission peak appears. This showed that the gather degree became higher. When in sol catalyzed by acid the dye molecules were wrapped in the hole together with water and ethanol

so the concentration in hole was higher than average. On the other hand

hydrolysis product began to polymerize after aging two days

and the product was water. So the proportion of water added in composite. These two aspects resulted in red shift. The pH degree was very high in sol catalyzed by alkali

this restrain dye molecules polymerize. Doped in silica gels

the C102 molecules were isolated and adsorbed in the tiny pores of the inorganic network steadily. Almost all of them existed in the form of monomer

so the spectra were similar to that of a single molecule. In structure

the sample catalyzed by acid had flat surface and dense structure

but it had hackly surface and open structure catalyzed by the alkali. All the results showed that the sample catalyzed by acid can be better used as a solid laser material.