As historical stone relics are heritages of glorious Chinese culture, their conservation is indispensable. At present, the main seal materials for stone conservation are organic macromolecule and polymer silicate of low molecule weight. Because of bas osmosis and strong solidification stress, the macromolecule has been limitedly used. On the contrary, having good osmosis, no solidification stress and high compatibility with stone materials, polymer silicate of low molecule weight is increasingly employed. In this work, a kind of polymer silicate of low molecule weight, polymerized by monomer MTEOS and TEOS, used to seal historical stone relics, was analyzed. The effects of the coating film with different monomer amount on the nature of seal materials are discussed, including adhesion, ageing resistance, gas permeability, soluble salt tolerance and ultraviolet radiation tolerance. Besides, analytical techniques such as IR and SEM were also used to study the materials. The experimental analyses indicated that during polymerization process, adhesion and dosage effect of the product were optimum when the MTEOS reaches 40%. And after sealing, the acidproof alkalinity, soluble salt tolerance, ultraviolet radiation tolerance, freezing and thawing tolerance got enhanced in vary degree. This research concludes that low polymer silicate ester can meet the request of sealing the historical stone relics.