α,ω-Trimethoxysilyl polyurethane modified with polyorganosiloxane JUMPS) sealant was prepared by adding additives, such as plasticizer, crosslinking agent, and viscosity increasing agent, to α,ω-trimethoxysilyl polyurethane modified with polyorganosiloxane hybrid elastomer at room temperature under nitrogen atmosphere. The TUMPS hybrid elastomer was crosslinked by the sol-gel reaction of methoxy group of TUMPS with hydroxyl group in the building stone and moisture of the air. It was found that TUMPS sealant exhibited more stable rheological and sealant properties than those of TUMPS hybrid elastomer. The shrinkage rate of TUMPS sealant was 5.82-6.0%, and skin over time was about 40 min. Alkaline resistance showed good characteristics for 15 days, slump was about 4.0-4.3 min, and oil content, as the diameter soaked oil from wetted filter paper was 1-2 min after 7 days.