Yttrium aluminum garnet (Y3Al5O12,YAG) transparent ceramic is the most widely adaped laser gain medium for solid state lasers,due to its excellent physical and chemical properties.It is generally reconogized that the property of ceramic powder determine the final performance of ceramic,and co-precipitation method is one of the promising techniques powder processing method for YAG ceramic.Compared with traditional high temperature solid state reaction method,which requires tedious mechanical mixing and prolonged heat treatment at high temperature,co-precipitation method has its advantage of narrow size distribution,good dispersion and high sintering activity.Since co-precipitation method has been developed for many years,until now,however,there is still some problems unsolved.For example,titration method is commonly applied in co-precipitation method,which is not benefit to the homogenetiy of solution.Also,due to the solubility product between Y3+ and Al3+ is different,and stoichiometric deviation easily occurred if the PH value is not controled precisely during the co-precipitation process[1].