Abstract: <SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: "Times New Roman"; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体">Alumina membranes were prepared by sol-gel process with aluminium isopropoxide as the main raw mate-rial after giving the raw material pretreatment and the membranes were formed on multichannel tubular</SPAN><SPAN style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 12.0pt; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-bidi-font-family: "Times New Roman"; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">α</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: "Times New Roman"; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体">-Al2O3supporters through dip-coating.Influences of raw material treatment modes on shortening the sol synthesis time and on product quality were discussed.Ultrafine filtration membranes whose performance indexes,such as pore size and membrane thickness etc.could be controllable were obtained by adjusting the concentration of slurry and the dip-coating time.Different drying tempe-ratures and modes were selected for drying gel and the morphologies of membranes at different drying conditions were observed by SEM.Results indicated that,it was very important to treat supporter and to control<SPAN style="mso-spacerun: yes">&nbsp; </SPAN>dip-coating time and viscosity in the gel membrane drying process in obtaining the smooth and flawless membranes,and high quality gel membranes could be obtained by adopting step drying mode under the steam protection.</SPAN>