A reinforcing material for the cultural relics of pottery that mixed inorganic and organic compound materials was prepared with PVAc and PVB modified-silica sols. PVAc-modified silica sols are used for the first time to enhance preserving cultural relics of pottery because of its permeability in the normal ambient temperature and pressure. After a great quantity of systematic experimental study (silica sols 30%-50%, PVAc 20%-40%, PVB 0.5%-1%), the optimum content of silica sols was determined. Comparing treated pottery and a piece of pottery untreated, the rate of water absorbency from 14.74% dropped to 5.06%, acid fastness from 95.53% increased to 98.73%, fastness to alkali from 97.61% increased to 99.34%, the compression strength incteased 47.09%, the bending strength increased 107.9%, and the appearance of cultural relics of pottery was not affected. The materials have some advantages: simple preparation, low price, easy operation, water solvent, nonpoisonous, and so on. Used as a reinforcing materials for cultural relics of pottery, it can be the optimum selection, which has some social and economic benefits. -- MCI