Abstract: Influence of filler compositions on the densification of Si₃N₄ ceramics under the condition of gas pressure-sintering have been studied and the β-Sialon ceramic materials with high density and high strength have been manufactured. Results show that taking advantages of Si₃N₄+BN+MgO or Si₃N₄+SiO₂ as filler can effectively control the decomposition of Si₃N₄ and promote the sintering of β-Sialon ceramics. Densificating mechanism of β-Sialon has been discussed in combination with X-ray and SEM analysis.