A new synthesis method of Si3N4 powder with a high alpha-phase content, namely reductive combustion synthesis, was pioneered in the present work. Some fundamental experiments were carried out and the result indicated that the content of alpha-Si3N4 increases with the addition of SiO2 and C, which considerably enhances the efficiency and drastically reduces the cost. The new method not only confers the advantage of carbothermal reduction and nitridation technology, but overcomes the shortcomings of a conventional combustion synthesis process.