Abstract: OBJECTIVE To observe the effect of chlorine dioxide gas on disinfection of environmental surfaces and high efficiency particulate air filter of B2 biological safety cabinet and evaluate the influencing factors.METHODS The Bacillus atrophaeus（ATCC 9372）spore was used as biological indicator to evaluate anti-microbial activity by qualitative sterilization test, the concentration of chlorine dioxide gas, temperature and humidity were monitored during the disinfection process.RESULTS Both the 900 g/L of chlorine dioxide gas raw materials reagent A（sodium chlorite）, 450 g/L of reagent B（salt of organic acid） and 150 g/L of reagent N（chlorine dioxide neutralized preparations such as sodium carbonate and sodium sulfite） working for 5 hours and the 1 200 g/L of reagent A, 600 g/L of reagent B and 200 g/L of reagent N working for 4 hours were able to kill all the point biological indicators completely.It was difficult to kill biological indicators in the downstream of exhaust of the high efficiency particulate air filter, because the concentration of chlorine dioxide and relative humidity were lower.CONCLUSION The chlorine dioxide gas can quickly kill the biological indicators on the surface and the upstream of supply high efficiency particulate air filter of B2 biological safety cabinet.The downstream of exhaust, where the diffusion path is longer and the filter is thicker, requires a higher reaction concentration and a longer dwell time to achieve the disinfection effect.