beta-cyclodextrin (beta-CD) immobilization of a chitosan derivate on C-6-OH (CTS-6-CD) with good solubility was prepared through a novel method. During the process the amino group of the chitosan was protected by phthalic anhydride and deprotected in the hydrazine hydrate solution. beta-CD was immobilized onto the C-6 position of chitosan by a nucleophilic displacement reaction. The prepared derivate can be dissolved in hydrazine hydrate (v:v = 1:1), ethylenediamine/ethanol (v:v = 1:1), 1% aqueous acetic acid, DMSO and DMAc. The application of the 6-OH cyclodextrin-immobilized chitosan derivatives in an electrochemical biosensor was examined in a preliminarily manner.