As the life of buildings is required to be extended, we tried to increase the durability of exterior wood by coating it with a paint that is a composite of organic-inorganic materials with excellent weather resistance. An accelerated weathering test comparing the durability of wood coated with various paints and an actual environmental exposure test simulating a wall surface were carried out. As a result, it was confirmed that the developed organic-inorganic composite paint has a durability improving effect on exterior wood as compared with general organic paints.