Abstract: Phase analysis,relative density testing and microstructure observation were used to study the effects of ternary carbide of Al4SiC4 as a sintering aid on pressureless sintering of β-SiC at different sintering temperatures.The results show that Al4SiC4 decomposed and produced Al during sintering process at high temperature.Al atoms entered into β-SiC crystal lattice,which could promote the transformation of β-SiC to α-SiC.With the increase of sintering temperature,the relative density of sintered samples increased.With the increase of Al4SiC4 amount,the relative density of sintered samples first increased then decreased.The sintered sample had a most compact structure with maximum relative density when the amount of Al4SiC4 was 5wt% and sintering temperature was 1 900 ℃.