Abstract: In view of the problem that according to the current safety regulations, early warning risk defects of CO sensors installed in mines prone to spontaneous combustion, a layout mode that comprehensively considering the CO high risk points and monitoring coverage was proposed. Comprehensive optimization layout model was established by means of graph theory and set covering theory, defining objective functions and constraints, column reduction-ant colony algorithm was used to optimize the solution, the column reduction algorithm was used to reduce the original monitoring coverage matrix for the constraint condition that the model contains the known mandatory layout points, then ant colony algorithm was used to solve the set of minimum full-coverage monitoring points, set the CO shortest effective alarm time 14.25 min which is the alarm time of mine tape machine roadway as the monitoring effective level. The simulation experiments show that the CO sensors arranged according to the correlative regulations and specifications are able to meet the actual requirements of mine engineering.