The invention relates to the field of chemical engineering, in particular to efficient fortifier for cardboard paper and a preparation method thereof. The efficiency fortifier is prepared from water-soluble polyether, polyvinyl alcohol, cationic polyacrylamide, bactericide, defoamer and deionized water, wherein one of pypocholoride, pypocholoride and pypocholoride is adopted as the bactericide, and one of organic silicon defoamer and polyether deformaer is adopted as the defoamer. The preparation method comprises the following steps that the cationic polyacrylamide is added into a reaction kettle, the deionized water is added, and the mixture is stirred until mixing is uniform; the water-soluble polyether is added, and the temperature is raised to 60-70 DEG C; the polyvinyl alcohol is added, the temperature is raised to 110-125 DEG C, the defoamer and the bactericide are added, the mixture is stirred until mixing is uniform, and the efficient fortifier for the cardboard paper is obtained. The efficient fortifier for the cardboard paper is environmentally friendly and capable of improving the breakage resistance and the fold resistance of the cardboard paper. The efficient fortifier can effectively reduce starch or even completely replace starch, and the cost of the follow-up workshop section is indirectly reduced.