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.