The present invention relates to a concrete surface coating agent which is waterproof and finishes the surface of concrete and a surface coating agent for preventing the deterioration of a steel structure. An organic and inorganic silicate coating finishing material for finishing the surface of concrete of the present invention comprises: polyvinyl alcohol as a base material; and silicate, wherein the polyvinyl alcohol is a hydrophilic polymer having excellent mechanical and chemical properties so as to be used in various fields such as those of fibers, films, coating agents, and surface treatment agents, is bio-degradable and has an excellent function of controlling oxygen penetration so as to be used for highly functional industrial materials, optical films including highly functional and polarizing films, and separation films, and takes water as a solvent and is non-toxic so as to be used as a clean material for environment-friendly and water-soluble fibers, The silicate is used to improve water resistance, which the polyvinyl alcohol lacks. The organic and inorganic silicate coating finishing material for finishing the surface of concrete of the present invention has excellent tensile strength, elongation, and abrasion resistance and has especially excellent oxygen-barrier properties, transparency, toughness, non-electrification properties, and gloss so that the material can be used as a surface coating material for preventing the deterioration of a steel structure and as a surface finishing material of concrete for an engineering or building structure. Also, the material has excellent finishing properties, fire retarding properties, and properties for preventing the deterioration of steel materials and concrete.