Chitin gel-membranes (CGM), which fabricated directly from chitin solution in NaOH/urea aqueous system at low temperature, were applied for in situ synthesis of Ag2Mo2O7 nanoparticles to obtain hybrid nanomaterials. The microporous structure of CGM at wet state was served as reaction chambers to synthesize the Ag2Mo2O7 nanoparticles. The structure and properties of the nanocomposite membranes were characterized with X-ray diffraction, thermal gravimetric analysis, scanning electron microscopy and Fourier transform infrared spectroscopy. The results indicated that the CGM film at dry state showed mesopore structure, and the Ag2Mo2O7 nanoparticles with average size of 10 nm dispersed uniformly along the wall and immobilized in the chitin matrix. There was a strong interaction between Ag2Mo2O7 and chitin, and the porous structure of the CGM matrix played an important role in the synthesis and immobilization of inorganic nanoparticles. Moreover, the Ag2Mo2O7/chitin membranes exhibited a significantly antibacterial activity even tested in the microbial broth. It could be explained that DNA lost its replication ability and the protein became inactivated due to the associating with the Ag+. The Ag2Mo2O7/chitin composite membrane would be an ideal candidate for the tissue engineering and wound dressing application. This work provided a novel and "green" pathway for the fabrication of the nanoparticle/ polymer hybrid materials, having great potentials in the biomaterial field. Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved.