Collagen peptide grafted carboxymethylated chitosan was synthesized by using microbial transglutaminase as bio-catalyst. The catalyzed reaction exhibited high efficiency, selectivity, environmental friendliness. Collagen peptide grafted carboxymethylated chitosan was characterized by Fourier transform infrared spectroscopy. The process conditions were optimized including the reaction time, the reaction temperature, the molar ratio of collagen peptide to carboxymethylated chitosan and the pH value. The different molecular weight, concentration and degree of substitution of collagen peptide-carboxymethylated chitosan had crucial effects on the hydrogen peroxide scavenging activity of collagen peptide-carboxymethylated chitosan. The methyl thiazolyl tetrazolium assay showed that at a suitable concentration collagen peptide-carboxymethylated chitosan with different degree of substitution value could promote L929 mouse fibroblasts effectively. Therefore, the results suggest that collagen peptide-carboxymethylated chitosan could be potential wound dressings for clinical applications. (C) 2014 Elsevier Ltd. All rights reserved.