Abstract: Effects of the alumina doped through normal co-precipitation on the sintering and properties of 8YSZ were studied.The result shows that with proper addition of alumina,the sintering temperature is decreased and the sintering density of zirconia is improved,the grain conductivity decreases with increasing content of added alumina,but if the content of added alumina is lower than 1.5wt%,the grain boundary conductivity is deteriorated instead of improved.