alpha-Si3N4 powders were fabricated through combustion synthesis (CS) process, and the effects of nitrogen purity and pressure on the combustion synthesis Of alpha-Si3N4 specimen with large dimensions were investigated. It is shown that there exists respective nitrogen pressure limits for the initiation and the propagation of the self-sustained combustion. Moreover, it is found that there is an optimum nitrogen pressure for synthesizing tailored alpha-Si3N4 powders while other parameters were kept constant.