With fused silica as the main raw material and sugar as carbon source, pretreats the fused silica powder for trace nitrogen introducing under the vacuum and nitrogen filling conditions. Makes thermodynamics and kinetics analysis on SiO2-N-C reaction system, and studies nitrogen introducing at different temperatures without affecting the fused silica powder phase change. Investigates the test results by means of X-ray diffraction analysis, Fourier transform infrared spectroscopy and electron microscope scanning EDS detection method. It shows that the introduction of trace nitrogen achieves at the pretreatment temperature of 1 050 ℃，holding time of 90 min and nitrogen flow rate of 5 L/min.