Abstract: FLUENT was used to simulate and comparatively analyze field test results in this paper in order to study the distribution and transport diffusion of CO concentration produced by mine flame-proof vehicle in underground tunnel, and to analyze the interference of CO emissions on coal spontaneous combustion forecasting and early warning underground. FLUENT was used to simulate the distribution of CO concentration when mine flame-proof vehicle run at speed of 7 m/s in underground tunnel while the inlet velocity was 3 m/s. Dynamic distribution of CO concentration discharged by mine flame-proof vehicle within t=1 s to 5 s was obtained, and variation of CO concentration on static monitoring points was obtained at the same time. The simulation results showed that the region of CO concentration greater than 24×10^-6 was in the scope of car tailgate to the back 6 m to 7 m, and it reduced to less than 24×10^-6 in 1 second. In front of car body, the CO concentration was always 19×10^-6. For comparative analysis, three monitoring points was arranged to monitor the CO concentration in actual underground tunnel. And the experimental results verified the correctness of the simulation results.