Abstract: Using a fuzzy inference algorithm,the paper put forward a method which took temperature and dense of carbon monoxide as two parameters to detect fire level of belt conveyor according to certain fuzzy rules table and inference rules and using barycenter method to fuzzify. The simulation result showed that when 0.5 is regard as alarm threshold, the system would alarm after belt conveyor fire took placed about 134 s.So it realized early forecast for belt conveyor fire.