A simple and low-cost composite film was prepared,based on which a sensitive detection method of lead ions(Pb2+) in aqueous solutions with naked eye was developed.Polyamide-6(PA-6) thin layer chromatographic membrane was selected to adsorb bovine serum albumin(BSA) modified gold nanoparticle(AuNPs),and a stable BSA-AuNPs/PA-6 nanocomposite film with a uniform red color was prepared.The adsorption time of BSA-AuNPs to PA-6 membrane,concentrations of Na2S2O3 and 2-ME as well as reaction temperature and time in the 2-ME-Na2S2O3-AuNPs/Pb2+ leaching system were investigated,which demonstrated obvious effects on the detection of Pb2+.Under the optimal conditions(BSA-AuNPs and PA-6 incubate together for 30 min,0.05 mol/L Na2S2O3,0.25 mol/L 2-ME,nanocomposite film and leaching agents incubate together at 80 ℃ for 20 min),the BSA-AuNPs/PA-6 nanocomposite film allowed for the sensitive detection of Pb2+ with naked eye with a sensitivity as low as 2.0×10-8 mol/L.The method showed a high selectivity,and was applied in the naked eye detection of Pb2+ in tap water with a detection limit of 5.0×10-8 mol/L.