Chitosan is a cationic biopolymer that has many electrochemical applications because of its ability to interact with anionic surface-active molecules. In present experiment, chitosan nanofibers were successfully deposited on indium tin oxide (ITO) substrates by electrospinning chitosan solution. After neutralization with saturated Na2CO3 aqueous solution to maintain its fibrous structure, alpha-[P2W18O62](6)- (abbr. P2W18O62](6-) was immobilized on the chitosan nanofibers by one step self-assembly technique. The scanning electron microscope (SEM) images showed that P2W18 was mainly deposited on chitosan nanofibers. The cyclic voltammetric responses showed three well redox couples Of P2W18.. Electrochemical behavior of the electrode prepared under different condition of pH value was investigated. In addition, the modified electrode exhibited high electrocatalytic activity for reduction of NO2-. (c) 2007 Elsevier B.V. All rights reserved.