With superfine alumina powder as the main raw material,aluminate cement as binder,sodium hexametaphosphate as water reducing agent,and chosing aluminum dihydrogen phosphate,the high aluminum phosphate ceramic was prepared by casting molding method.The effect of holding time,calcination temperature and aluminum dihydrogen phosphate content on the properties of phosphate ceramic were studied.Results showed that adding aluminum dihydrogen phosphate can improve the property of high aluminum ceramic;when aluminum dihydrogen phosphate content was 6%（mass fraction）,high aluminum ceramic flexural strength was 24.15 MPa.When the aluminum dihydrogen phosphate content was more than 6%（mass fraction）,which was unfavorable to the bending strength of high alumina ceramics.Adding 6% of aluminum dihydrogen phosphate to form the main phase was quartz,corundum,phosphate,sillite and mullite.The addition of aluminum dihydrogen phosphate facilitated the formation of new phase of ceramics.Suitable preparation conditions of high aluminum phosphate ceramics were as follows：the dosage of bauxite powder was 96%（mass fraction）,the dosage of aluminate cement was 4%（mass fraction）,the dosage of water reducer was 0.1% plus（mass fraction）,the dosage of aluminum dihydrogen phosphate was 6% plus（mass fraction）,the holding time was 4 h and the calcination temperature was 1 250 ℃.