The invention discloses a modified biological filtering pool filler and relates to a modified filler applied to an aerated biological filtering pool and a method for processing the same. An inorganic filler ceramic particle, lava or porous ceramic, which is used as a carrier, is subjected to pickling, alkali cleaning, drying, sterilization and other processing procedures and is dipped in a dilute aqueous solution containing cationic polyacrylamide (Polyacrylamide, abbreviated as PAM) so that the inner surface of the filler is modified to obtain an inorganic carrier of which the surface of an inner hole is formed with a polymer molecular body with positive charge; and the inorganic carrier is domesticated to generate the immobilized microorganism filler. Through double functions of physical adsorption and ionic bond combination, the filler improves physicochemical performance and washing resistance performance of the immobilized microorganism for inorganic carrier, is favorable for improving loading amount of microorganism and domestication and proliferation of the microorganism, saves the cubage of a reactor, shortens reaction time, improves efficiency biological denitrification and saves investment.