AlO-ZrOmicrospheres were prepared by internal gelation method.The effects of Alon the stability of solution and performance of gel spheres were studied.Alhad a great influence on the stability of the solutions,and the more of the amount of Al,the shorter of the stabilization time.Because Aldid not copolymerize with Zrduring the sol-gel transformation,the strength of gel sphere added with Alwas low and deformed easily as it was squeezed.The results of our experiments well verify Glasser team’s speculation and conclusions.At the same time,based on the experimental results,we prepared AlO-ZrOcomposite microspheres with higher content of AlOby controlling the pH of the solution.The change curve of viscosity with time and the stabilization time of the solution with different Aldosage were given,which could provide references for industrial mass production.Samples without hydrothermal treatment cracked severely,while the samples hydrothermally treated kept structural integrity with no cracks after calcined.AlO-ZrOmicrospheres with no segregation and phase separation were prepared and alumina evenly distributed in the zirconia matrix.When the content of AlOwas low,the tetragonal phase was stable.And the cubic phase was obtained when the content of AlOwas more.