Abstract: Provided is a concrete hardener composition. The concrete hardener composition includes a sodium silicate compound, an acid compound and a balance amount of solvent. The sodium silicate compound includes sodium silicate or a mixture of sodium silicate and sodium methylsilicate. The acid compound includes acetic acid, glycolic acid, ethylenediaminetetraacetic acid, tartaric acid, nitric acid, boric acid or a combination thereof. The solvent includes water or a mixed solution of water and polyol. Based on the total weight of the concrete hardener composition, the content of silicon is between 5 wt % and 15 wt %, and the content of the acid compound is between 2 wt % and 30 wt %.