Six compositions with different ratio of β-Sialon/Al2O3 were synthesized from Al2O3, Si3,N4 and SiO2 by sintering with 3%Y2O3(mass fraction) as addition under the cover with powders of SiC+C and at nitrogen atmosphere. Theeffects of atmosphere, sintering temperature and composition on the sintering behavior were studied. The results showedthat the composites reached the best sintering behavior with the highest density about 92% at 1 650℃ under the weakreduction atmosphere. Finally the relative density of diphasic β-Sialon and p-Sialon/Al2O3 composites were studied andpredicted using ANN (Artificial Neural Networks) method and the results were experimental examined by fore randomsamples. Six compositions with different ratio of β-Sialon / Al2O3 were synthesized from Al2O3, Si3, N4 and SiO2 by sintering with 3% Y2O3 (mass fraction) as addition under cover with powders of SiC + C and at nitrogen atmosphere. The effects of atmosphere , sintering temperature and composition on the sintering behavior were studied. The results showed that the composites reached the best sintering behavior with the highest density about 92% at 1 650 ° C. under the weak reducing atmosphere. Finally the relative density of diphasic β-Sialon and p- Sialon / Al2O3 composites were studied and predicted using ANN (Artificial Neural Networks) method and the results were experimental examined by fore randomsamples.