Abstarct: Heavy mextals¬ (HM) are among the most significant pollutants in the environment. The introduction of toxic mextals like lead (Pb) through human activities has led to substantial contamination of soils. The presence of these HM in soil and their accumulation in plants growing in these soils will have adverse effects on both the plants and consumers. One approach to reducing the accumulation of heavy mextals and the negative effects resulting from them in plants is the use of amino acids. Therefore, this research was conducted in the years 2019 and 2020, both in field and pot experiments, to investigate the effect of lead and the role of foliar application of sulfur, serine, and glutamine in reducing its damage in green bean plants. For this purpose, an experiment was conducted in a factorial design in the form of a randomized complete block with three replications in two parts: field and pot experiments at the Mashhad Agricultural and Natural Resources Research Center. Treatments in field conditions included lead foliar spraying at two levels (zero and one mM) from a Pb acetate source 39 days after planting, liquid sulfur spraying at two levels (zero and two per thousand), and amino acid foliar spraying at four levels (zero, Ser, and Glu each at 200 mg per liter, and simultaneous use of Ser and Glu at the same concentration) applied before flowering. Treatments in pot conditions involved the application of lead at four levels (zero, foliar spraying with a concentration of 1 millimolar, soil application with a concentration of 250 mg per kg of soil, and combined application of foliar spraying and soil use at the same concentrations) from a lead acetate source as the first factor, liquid sulfur spraying at two levels (zero and 2 per thousand) as the second factor, and amino acid foliar spraying at four levels (zero, serine and glutamine each at 200 mg per liter, and combined use of Ser and glu at the same concentration) as the third factor. Soil contamination with lead was conducted two weeks before planting. Lead spraying was done 30 days after planting in the pre-flowering stage, and S, Ser, and Glu spraying started 14 days after the lead treatment, with a one-day interval between each. The results of the field section showed that foliar absorption of lead caused a decrease in leaf area index, dry weight of leaf, stem, and sheath, stem diameter and height, sheath yield, photosynthetic pigments such as chlorophyll a, b, and carotenoids, and relative leaf water content, while seed protein, hydrogen peroxide, and glutathione content increased significantly. Also, with foliar absorption of lead, the number of sheaths per plant, thousand-seed weight, seed yield, and sheath decreased, but the foliar spraying of amino acids and sulfur reduced the negative effects of lead. The use of sulfur, serine, and glutamine treatments alone and in combination increased lead accumulation in green bean leaves and reduced it in stems and sheaths. The combined application of treatments showed greater effects, as the simultaneous use of S+Ser+Glu increased lead in leaves by 87.4% and reduced the accumulation of this heavy mextal in sheaths by 60.8% as a food organ of green beans. The lowest Pb accumulation in the stem was obtained under Ser, Glu, and different combinations of treatments, although the treatments did not show significant differences from each other. The spraying of S, Ser, and Glu solutions was effective in reducing the negative effects of Pb stress, as it led to a decrease in hydrogen peroxide levels, seed protein, and enhancement of the glutathione reservoir. The results of the pot section showed a reduction in leaf area index, stem length and diameter, and relative leaf water content at all levels of Pb along with an increase in malondialdehyde content. Additionally, antioxidant enzyme activity, including catalase, ascorbate peroxidase, and glutathione S-transferase along with non-enzymatic antioxidant glutathione, significantly increased compared to the control treatment. All studied traits, except malondialdehyde, improved under the influence of sulfur and amino acids, Ser and Glu, at all three pb levels. The examination of lead accumulation in leaves, sheaths, stems, and roots under Pb stress indicated that the use of S, Ser, and Glu Pb to an increase in lead concentration in leaf, root, and stem tissues while reducing the accumulation of this toxic mextal in the edible part of green beans. The results of this study demonstrated that the foliar application of S, Ser, and Glu under Pb stress conditions could detoxify lead, increase plant tolerance to Pb stress, and provide humans with healthier food by enhancing antioxidant defense systems.