A novel saccharide sensor based on the covalent interaction between the boronic acid and saccharides was developed. Poly (aminophenylboronic acid) (PABA) was prepared by electropolymerizing 3-aminophenylboronic acid on gold electrode surface in acidic solution. The boronic acid group of the PABA film can form covalent-bond with different saccharides, which can change the dielectric characteristics of the PABA film, and the change of the dielectric characteristic was saccharides concentration dependent. Four kinds of saccharides could be detected by using electrochemical impedance spectroscopy. Good linear relationship and high sensitivity were obtained by this method. (c) 2005 Elsevier B.V. All rights reserved.