Preparation method for cationic-type activated carbon

The invention relates to a preparation method for cationic-type activated carbon. The preparation method comprises the steps of washing, drying and crushing activated carbon, and oxidizing the activated carbon by concentrated hydrochloric acid or sulfuric acid so that the surface of the activated carbon has hydroxy; heating to the temperature of 80-87 DEG C under the condition of water bath, then adding epoxy chloropropane and N-N dimethylformamide, and stirring and reacting for 0.5-1.5h; and adding ethanediamine to react for 1-1.5h, then continuously dripping triethylamine to react for 0.5-1h, cooling to room temperature, and washing and drying so as to obtain the cationic-type activated carbon. An activated carbon product is the cationic-type activated carbon with positive charges, has a cationic group and a hydroxyl group, further has biodegradability, and is applicable to removing anionic-type pollutants in water.