A non-premixed combustion model was established based on the chamber structure and heat transfer characteristics of a 2 t/h horizontal shell oil-fired boiler, and the effect of wind speed on the mist combustion and emission characteristics of soot particles analyzed. The results showed that the fuel concentration in the chamber rapidly reduced along the axial direction in 0.3~0.7 m from the fuel nozzle. The soot particles were quickly generated in the mixed combustion zone from the fuel nozzle of 0.3~1.5 m, and went away from the nozzle with increasing of wind speed. The largest generation rate appeared at the ignition point. When the wind speed was too big or too small, the generated soot particles increased. When the wind speed was 7.5 m/s, the soot concentration was the smallest and most evenly, and its value was 0.042%(w).