发明了一种纳米级球形氧化铝的制备方法，属于氧化铝加工技术领域。发明的纳米级球形氧化铝的制备方法，包括以下步骤：1）将可溶性铝盐、柠檬酸铵、水与乙醇混匀后于150～200℃溶剂热反应15～24h，之后冷却，过滤得产物，将产物进行干燥，得前驱体；2）将步骤1)所得的前驱体于400～600℃保温2～7h即得。发明的纳米级球形氧化铝的制备方法，突破了现有技术中采用尿素、氨水、氢氧化纳等碱性物质制备球形氧化铝的限制，且发明方法所得的氧化铝形貌规整，无明显团聚，颗粒尺寸细小，达到纳米级别，具有好的应用前景。

The invention discloses a preparation method of nano spherical alumina, which belongs to the technical field of alumina processing. The preparation method of nano spherical alumina comprises the following steps: 1) mixing soluble aluminum salt, ammonium citrate, water and ethanol, solvothermal reaction at 150~200℃ for 15~24h, then cooling, filtering to obtain the product, drying the product to obtain the precursor; 2) The precursor obtained in step 1) is obtained by holding at 400 ~600℃ for 2~7h. The preparation method of nano spherical alumina breaks through the limitation of preparing spherical alumina by using alkaline substances such as urea, ammonia and sodium hydroxide in the prior art, and the alumina obtained by the invention has regular morphology, no obvious agglomeration, small particle size, reaching the nano level, and has good application prospects.