Abstract: The exhaust gas emitted by vehicles in idling underground chamber of coal mine seriously threatens the occupational health of coal miners. Taking the 25211 working face chamber of Hongliulin Company and the WC19R(A) rubber-tyred truck as the research objects, a component transport model was constructed based on the Euler method, simulated and analyzed the diffusion characteristics of NO, NO2 and CO exhaust gas in the tunnel under the influence of different roadway wind speeds. The results show that: when the wind speed exceeded 1.0 m/s, due to the increase of the wind speed in the roadway, the exhaust gas was affected by the lateral vortex in the chamber, and the phenomenon of diffusion to the chamber mouth was gradually significant; the gas followed Fick's law in the process of diffusion, and the exhaust gas concentrations on both sides reached their peaks at about 9.0m and 1.0m from the chamber mouth, respectively, and the fitting functions of the three gases were obtained at the same time. After on-site verification, the error between the simulation results and the on-site test results is less than 23.7%.