Abstract: Local exhaust hood is the most effective way to control the buoyant jet with contaminants in industrial buildings． The control effect of the exhaust hood decreases due to the area of hood smaller than the pollutant source because of the internal structure of the industrial plants or their process conditions． regarding this issue，numerical analysis methodology was adopted to study the changing law of buoyant jet flow field under the condition of space confined． A more energy saving method was presented compared to increasing the exhaust air flow rate． Subsequently，the influence law between baffle and capture efficiency was illustrated． Eventually，the result showed that the rational baffle set could highly increase the exhaust hood capture efficiency． Furthermore，the capture efficiency improved along with the increase of dimensionless length of the baffle． The baffle effect was able to reduce the lessening influence upon the capture efficiency caused by increasing the height of hood．