A mixture of aluminum isopropoxide (Al(OC3H7i)3) solution and sodium hydroxide (NaOH) solution was hydrolyzed in the range between pH 1~14. the powder obtained from sol-gel process was calcined at several temperatures and crystallization behaviors of various samples were investigated. The hydrolyzed sols of pH 1~6 wre clear, or near clear. On the other hand, powder precipitated from sols of pH 7~14. The sample obtained from pH 3 solution crystallized via complicated route, and $eta$-Al2O3 and $eta$"-Al2O3 phases appeared at lower temperature than samples from other pH conditions. And the quantity of remained $eta$"-Al2O3 phase after heat treatment at 150$0^{circ}C$ was more than samples from other pH conditions. After sintering, ionic conductivities were 1.3$ imes$10-4S.cm-1 to 0.76$ imes$10-4S.cm-1.0-4S.cm-1.