Abstract: It is very important to find a effective method to extract the extracelluar polymeric substances (EPS) including polysaccharides, proteins and DNA, which have a significant role in the metabolism of the cells and the mass transfer of substrate within the biofilms, from biofilms without destroying its structure. In this study, a novel method to extract the EPS from intact biofilm was set up, based on the enhancement of external alternating electric field. The results showed that the current had insignificant effect on the cells structure, but it could enhance the extraction rate when charged extractant is used. In the range from 10 Hz to 500 Hz, the extraction rate increased with current frequency.