Abstract: OBJECTIVE To establish a method for isolation, purification and quantification of bacterial capsular polysaccharides (CPS) and lipopolysaccharides (LPS) without rupture of bacteria so as to provide options for clinical development of bacterial polysaccharide vaccines. METHODS Four common species of bacteria causing clinical infections were recruited as the research subjects. The bacterial LPS were isolated by ethylenediaminetetraacetic acid (EDTA), the bacterial CPS were isolated by 3-(N,N-Dimethylmyristylammonio) propanesulfonate (Zwittergent 3-14), the LPS were quantified by using phenol-sulfuric acid method; the CPS were quantified by uronic acid determination; LPS and CPS were purified by sevage method and anhydrous ethanol. The morphological structures of the bacteria were observed and compared by transmission electron microscopy, and the components of polysaccharides were determined by ion chromatography. RESULTS The polysaccharide contents of LPS extracted from Klebsiella pneumoniae, Escherichia coli and Acinetobacter baumannii were (1.10±0.26), (1.08±0.10) and (1.34±0.30) μg/10⁹ , respectively. The uronic acid contents of CPS extracted from K.pneumoniae, E.coli, A.baumannii and S.aureus were (13.83±2.31), (3.35±1.83),(12.95±4.47) and (6.88±2.09) μg/10⁹, respectively. Transmission electron microscopy showed that the structure of cell membrane was intact, and the cell was not broken after treatment. The chromatographic results confirmed that the isolated extracts contained common components of CPS and LPS. CONCLUSION This method can effectively isolate and quantify CPS and LPS without rupture of bacteria.