N, O-carboxymethyl chitosan (NOCC) composite nanofiltration (NF) membranes were prepared by coating and cross-linking. The fermentation effluent from a wine factory was treated with the resulting NOCC/polysulfone (PSF) composite NF membranes. The permeate flux and the removal efficiencies of the resulting NF membranes for the color, chemical oxygen demand (CODCr), total organic carbon (TOC), and conductivity of the fermentation effluent were investigated in relation to the driving pressure, the feed flow, and the operation time. The permeate flux and the removal efficiencies were found to increase with the increase of the driving pressure or the feed flow. At 0.40 MPa and ambient temperature the removal efficiencies were 95.5%, 70.7%, 72.6%, and 31.6% for color, CODCr, TOC, and conductivity, respectively. The membrane was found to be stable over a 10-h operation for the fermentation effluent treatment.