Ultrathin alumina hollow fibers were prepared by a phase inversion and a sintering method. A polysulfone solution containing well-dispersed alumina powders is spun, which is then sintered at elevated temperature. To increase the packing density of alumina powers in the hollow fiber, 1,4-dioxane was added as a nonsolvent in the polymer solution. The pore size and the porosity of the prepared alumina hollow fiber were 0.2 mu m and more than 40%, respectively.