Flame retardation of PET/cotton(35/65) blend fabric was carried out via UV curing of Bis[2-(methacryloyloxy)ethyl] phosphate(DMEP), triethanol amine(TEA), trimethylol propane triaerylate(TMPTA) and melamine phosphate(MP). Optimal TEA and TMPTA were found to be 5 and 10% on weight percentage of the monomer respectively. Particularly the addition of MP particles increased the flame retardancy of the blend fabric remarkably. The LOI of 25.9 was achieved by the UV coating of DMEP without MP addition. The highest LOI value of 28.1 was obtained with the addition of TEA and MP, which was durable to five laundering cycles. The obtained flame retardaney of UV-coated blend fabrics may result from a condensed phase mechanism as indicated by lowered thermal decomposition temperatures, higher carbonaceous char content with higher residue number, which reduces the generation of flammable materials by changing the pyrolysis path of the blend fabrics.