Surface photografting modification with maleic anhydride (MAn) under UV irradiation in association with a post reaction with triethanolamine has been used to improve the flame retardancy of polyamide6.6 (PA6.6) fabric in this study. The effects of irradiation time and monomer concentration on the fabric surface grafting were investigated. The flame retardancy and thermal decomposition behavior of the samples were characterized by limiting oxygen index test (LOI), thermogravimetric analysis (TGA), and differential scanning calorimetric (DSC), and the results indicate that flame retardancy of the treated PA6.6 fabric samples has been significantly improved. The chemical structures of the treated samples' surface were characterized by attenuated total reflection infrared spectroscopy (ATR-FTIR), and the possible photochemical mechanisms were discussed. It is suggested that this could be the first time to use photografting technology to enhance the flame retardancy of PA6.6 fabric. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 119: 66-72, 2011