A new consolidation in-situ forming process for high-performance alumina ceramic using acetate starch was investigated. The pasting behavior and thermogelling properties of acetate starch and the effects of different amount of acetate starch and solid loading on the rheologic behavior of the ceramic slip, as well as the linear shrinkage, density, strength and microstructure of the green body were discussed. The results indicate that acetate starch paste has good thermal stability and gelling ability. When the content of acetate starch is about 0.5%~1.5% (mass fraction), the apparent viscosity of alumina slurry, which is always less than 1Pa·s even for 58% (volume fraction) dense suspension, increased with increasing the acetate starch content and solid loading. That results in easier to cast. Moreover, with the increasing of solid loading the linear shrinkage and dry strength of green bodies decreased and the relative density increased. With the increasing starch content, the linear shrinkage rate and the density of the dried body decreased, while the strength of the dried body almost linearly increased. The green body with homogeneously-distributed density and pore size was also obtained in this work. It is concluded that Al2O3 ceramics can be consolidation in-situ formed based on the gelling network of thermally swelled and gelatinized acetate starch.