A convenient method of preparing chelating fiber with amine groups on the fiber surface was developed. The precursor polymer of Poly(N-vinylformamide/acrylonitrile) (P(NVF/AN)) was synthesized via solution polymerization, using N-vinylforaimde as a functional monomer. The solution of P(NVF/AN) was spun through a wet spinning method and the precursor fiber was hydrolyzed in the hydrochloric acid solution to convert formamide moieties to the corresponding amine. The influence of hydrolytic conditions on hydrolysis degree, such as hydrolysis temperature, hydrolysis time, and hydrochloric acid concentrations were examined experimentally. The hydrolysis degree of the precursor fiber was evaluated by potentiometric and conductometric titrations. The changes of the structure and properties of the fibers were characterized through infrared spectroscopy, scanning electron microscopy, and tensile strength tester. The results showed that the hydrolysis degree was limited in acidic hydrolysis because of the electrostatic repulsion among the cationic amine groups and proton. The hydrolysis degree of precursor fiber reached nearly 60%, and the chelating fiber remained the adequate mechanical properties under the suitable hydrolysis condition. (C) 2008 Wiley Periodicals, Inc.