Abstract: The equipment and its operating characteristics of purifying waste gas containing low concentration toluene by using biological method were investigated.The results showed that the purification performance of a packing column with biofilm-material packing was better than that with sieve-plate column and bubble column.When the biofilm-packing column was operated countercurrently under the conditions of liquid/gas ratio of 0.03～0.1 and gas velocity（30～60）m·h~-1，more than 90％ of toluene in the waste gas could be removed.It was confirmed in the experiments that the biofilm-packing column also could remove toluenes homologues from the waste gas.It was found that the biofilm-packing column showed good capability for removing toluene and other organic compounds from waste gases,exhausted by some industrial processes,such as regeneration of rubber,printing process,treatment of casting and paint production.