FIELD: chemistry. SUBSTANCE: invention relates to a method for the synthesis of aluminum oxide powder. The method includes the stages of bringing into contact acidic solution, which is acidic solution of aluminum nitrate, and main solution, which is an aqueous ammonia solution, heating the suspension at a temperature from 50 to 200°C for at least 5 h, filtering, drying at a temperature from 50 to 140°C for at least 1 h, and roasting at a temperature of at least 500°C. The method is characterized in that bringing into contact acidic solution of aluminum nitrate and aqueous ammonia solution is carried out at a room temperature, the pH value is ranging from 5.2 to 6.2, and during the whole process of bringing into contact acidic solution of aluminum nitrate and aqueous ammonia solution, the pH value does not change more than by 0.3 units due to discrete supplying aqueous ammonia solution. The process of bringing into contact acidic solution of aluminum nitrate and aqueous ammonia solution is carried out during the period from 1 to 10 h. After bringing into contact acidic solution of aluminum nitrate and aqueous ammonia solution, the pH value is increased to the value selected from the range from 8.0 to 9.5 by supplying aqueous ammonia solution. EFFECT: proposed method allows producing aluminum oxide powder with slit-like pore type, reducing the number of process stages, reducing energy intensity and time costs. 2 cl, 4 dwg, 4 ex.