Abstract: This study chose the 300 automatic epidemic prevention system of space electric air purification and the 3DDC-12 deodorizing and sterilization system of plasma in manure gaps (both for short automatic epidemic prevention system) to determine the effect of cleaning the air in the henhouses in winter. The comparative trials were carried out in two henhouses with same poultry density, same ventilation and temperature controlling system. With the automatic epidemic prevention system installed in the experimental henhouse, the concentration of harmful gases, air microorganisms and dusts under certain conditions were measured in both henhouses. The results of Experiment 2 showed that under proper ventilation conditions which kept room temperature at 14.2±0.4℃, automatic epidemic prevention system resulted in reduced air concentrations of microorganism, dusts and a lower mortality number in the experiment henhouse by 34.2%, 35.9%, and 46.0% respectively than what did in control henhouse (17.8 vs. 11.72 cfu/L, P<0.01; 5.52 vs. 3.54 mg/m3, P<0.01; 4.68 vs. 2.53 per day, P<0.01). The result showed that the automatic epidemic prevention system could significantly decrease microorganism, air dusts and the mortality rate.