This paper presents the preparation of β-Si 3 N 4 rod-like crystals that have an average aspect ratio of ~10 by combustion synthesis of the mixture of Si, α-Si 3 N 4 and Y 2 O 3 under 5 MPa nitrogen pressure. By using a quenching device, the growth morphology of β-Si 3 N 4 rod-like crystals was observed and it is concluded that the growth mechanisms result from the synergy of VLS (vapor-liquid-solid) and VS (vapor-solid).