To accurately determine the assignments of IR absorption peaks for 2, 6-diamino-3, 5-dinitropyrazine-1-oxide (LLM-105), the process of change in IR absorption peaks of LLM-105 under the heating conditions was investigated by temperature-dependent FT-IR spectroscopy. The positions of various IR absorption peaks at different temperatures were determined. Results show that with increasing the temperature, the strength of intermolecular hydrogen bond for LLM-105 is significantly weakened. IR absorption peak positions of amino group (—NH₂) and nitro group (—NO₂) participated in forming hydrogen bonds shift at least 4 cm^-1. The pyrazine ring and C—N bond do not participate in the formation of hydrogen bonds, their peak positions shift about 1 cm^-1.