In Our research work, it is revealed that during the treatment of artificial prepared detergent industrial wastewater, the tower biological filter can adapt to and overcome the foaming problem which can not be solved by other general aerobic biological wastewater treatment methods, and that it can reduce the amount of LAS and COD from the wastewater to some extent. The dominant species of bacteria in the biological membrane of the filter has been isolated, and identified as Aeromonas sp.D-4. Aeromonas sp.D-4 can not use LAS as the sole carbon source, but it utilizes LAS through the course of cometabolism. The maximum removal rate of LAS appears at the last stage of the stable phase of the bacterial growth, and is inversely proportional to the beginning concentration of LAS. When the beginning concentration of LAS is between 40-120 mg/l, comparatively higher removal rates can be obtained, and the removal rate will be higher than 80% when the beginning concentration of LAS is about 40 mg/l. It is also found that the removal rates acquired when pure culture of Aeromonas sp. D-4 is used (Max.84.97%) are higher than those obtained when mixed bacteria are used instead (Max.78.57%). LAS is toicant to Aeromonas sp. D-4 and the toxicity will be higher when higher concentrations of LAS exist in medium. The removal of LAS by Aeromonas sp. D-4 is achieved through the combined reaction of absorption and degradation of LAS by the bacteria.