Abstract: The paper analyzed development course and characteristics of mine spontaneous combustion fire monitoring system with beam tube at home and abroad, and indicated mine spontaneous combustion fire monitoring system with beam tube developed by Australia can reflect change trend of main gas in spontaneous combustion areas in time, so as to provide effective pre-warning for mine spontaneous combustion fire. The application result in fully-mechanized face of a coal mine shows that volume fraction of O2 of goaf gradually decreases with advancing of fully-mechanized face, the volume fraction of O2 of deep edge of the goaf is 5%～6% and becomes stable; the volume fraction of O2 of the goaf still keeps above 8%, so it should take corresponding technology measures to prevent phenomenon of spontaneous combustion of residual coal in the goaf within 100～150 m of the fully-mechanized face; the goaf is in asphyxia state beyond 150 m of the fully-mechanized face.