The invention provides a preparing method of a biological purification carrier for wastewater treatment. The preparing method comprises the following steps of mixing pretreated attapulgite with MBAA in saline water, and stirring the mixture at 50-70 DEG C for 1-3 h; mixing a biopolymer solution with the mixed solution, heating the solution to 40-60 DEG C, adding activated sludge of which the massaccounts for 2-5% of attapulgite and nanometer ferromanganese composite oxide of which the mass accounts for 1-3% of attapulgite, and adding a carbon nano tube of which the mass accounts for 2-5% of attapulgite to be stirred at the speed of 5-10 r/min for 1-3 h; then adding a cyclodextrin compound solution into the mixed solution, stirring at 20-30 DEG C for 20-40 min, placing the mixture at 10 DEG C for 30 min, adjusting the temperature to minus 5 to minus 7 DEG C, maintaining the temperature for 40-60 min, slowly stirring, conducting curing crosslinking, covering the mixture with gauze, extruding the gauze till water comes out, and using a 10-20% tannic acid solution for washing 2-3 times; placing the mixture at a drying oven at the temperature of 50-70 DEG C to be treated for 8-10 h. Bymeans of the preparing method of the biological purification carrier for the wastewater treatment, the sewage treatment efficient and capability can be effectively improved.