The iron-based biomimetic compound was used as the mimic enzyme for the delignification of pulp and paper wastewater in this work. It was prepared by ferric sulfate and polycarboxylic acid (PA), forming the Fe-PA complex. The XRD pattern of the Fe-PA complex and its delignification mechanism were discussed. The optimal control conditions of Fe-PA complex on delignification were evaluated by using the Fe-PA complex in practical applications. The XRD pattern reflected the characteristic of a stereochemical cell with iron as the active center in Fe-PA complex, and the delignification mechanism of the Fe-PA complex was based on the complexation and flocculation. The optimal control conditions of Fe-PA complex on delignification were determined and the results showed as the dosage of Fe-PA complex (0.6 mmol/L), dosage of H2O2 (60 mg/L), pH of the reaction system (5.5) and contact time (30 min). In addition, the excellent effect and low cost of Fe-PA complex in practical applications were determined by comparing those of conventional flocculation method, and these results illustrated an effective and economical method in pulp and paper wastewater treatment. (C) 2011 Elsevier B.V. All rights reserved.