The present invention provides a glass fiber board comprising a glass fiber and an inorganic binder, wherein the inorganic binder comprises an aluminum phosphate.The present invention provides a method for preparing the glass fiber board comprising (a) preparing an inorganic binder solution comprising an aluminum phosphate (b) applying the inorganic binder solution comprising the aluminum phosphate to a glass fiber; (c) compressing the glass fiber to which the inorganic binder solution comprising the aluminum phosphate is applied; and (d) drying the compressed glass fiber.