Abstract: The current study reported the method to extract extracellular polymeric substances (EPSs) from Achnanthes javanica var. subconstricta and analyzed compositions of the EPSs. The results showed that the optimal extraction condition was 0.3 mol/L NaHCO3 with 2.53h extraction time, which produced little lysis. Polysaccharide is the main component of EPSs that contributed more than 80% of EPSs, while protein contributed 16%19% of EPSs. There is no lipid in the EPSs. The monosaccharide composition of flucose, galactose, glucose, mannose, xylose, and rhamnose in water-soluble polysaccharide is 2.47:2.13:1:0.69:0.57:0.46 (molar ratio). The monosaccharide composition of galactose, flucose, xylose, glucose, mannose, and rhamnose in non-water-soluble polysaccharide is 3.56:2.73:1.30:1:0.67:0.57.