Change of cell surface features of Stenotrophomonas maltophilia in treating BaP and Cu2+ composite pollutants was studied.The results indicated that S.maltophilia was of higher cell surface hydrophobicity(CSH).It could keep within 83.3%—95.6% in treating different pollutant systems for 4—72 h，and then the CSH decreased with increase of operation time.BaP and Cu2+ can make permeability of the cell membrane increase.The morphological features of S.maltophilia observed by TEM showed that cell membrane ruptured and appeared holes on it after treating pollutants，leading to permeability change of cell membrane and outflow of the cytoplasm，but cell wall still kept the cell in original shape without complete splitting.However，after contacting combined pollutants for 5 day，bacterial cells were out of shape seriously，periplasmic space enlarged，and cytoplasm leaked，nucleus broke down and gradually disappeared，resulting in decrease of cell activity and in gradual loss of S.maltophilia’s ability adsorbing heavy metals.