A porous alumina with cylindrical pores was fabricated by unidirectional solidification under hydrogen gas flow (0.1 MPa) using alumina feed rods doped with silica, calcia or sodium oxide. The additives in the feed rods strongly affect the formation of porous structure during the solidification. The porosity increases with increasing silica content. The increase of porosity is enhanced by further addition of sodium oxide. The addition of calcia to the feed rod is effective on the homogenization of pore distribution. The porous alumina with 1mol%CaO and 20mol%SiO2 additives showed 50% porosity and homogeneous pores distribution.