Abstract: Taking ‘Xinxiang No.8’ pepper varieties as materials, the phthalic acid（PA） treatment(0.50、0.75、1.00、1.25、1.50、1.75、2.00 mmol·L^-1) on seed vigor index, radicle length and physiological and biochemical indexes of pepper leaves were studied by indoor hydroponic method, in order to provide theoretical basis for the allelopathy of pepper.The results showed that, 0.50 mmol·L^-1 PA significantly increased seed viability index, promoted radicle growth, increased chlorophyll content and maximum photochemical efficiency（Fv/Fm） in seedling leaves, and 0.75 mmol·L^-1 PA significantly increased H₂O₂ content and antioxidant enzyme activity, while 0.75 mmol·L^-1 PA significantly increased seed viability index, promoted radicle growth, increased chlorophyll content and maximum photochemical efficiency（Fv/Fm） in seedling leaves.When the concentration was higher than 0.75 mmol·L^-1,the seed vigor index and radicle length were significantly reduced by 50.17% and 57.04% in 1.50 mmol·L^-1 PA.After PA treatment, the soluble protein content（SP）,the activities of APX,CAT and POD in seedling leaves increased firstly and then decreased, the activity of SOD kept decreasing, and the content of H₂O₂ decreased firstly and then increased.In conclusion, pepper seedlings can resist PA stress by increasing SP content, protective enzyme activity and decreasing H₂O₂ content.