The effects of different concentrations of Arctium lappa L. extract on spinach's growth and quality were studied by pot experiment. The results showed that the fresh weight of spinach increased by 10.8% - 30.0% after spraying Arctium lappa L. extract which concentrations ranged from 30 mg/L to 1500 mg/L, the content of chlorophyll decreased by 2.7% - 15.7% which may be attributed to the “dilution effect”, the content of Vc increased by 46.1% - 136.4%, the content of nitrate decreased by 23.2% - 69.2%, the content of oxalate decreased by 22.3% - 67.6%. The contents of chlorophyll,Vc, nitrate and oxalate of spinach which treated by 30 mg/L Arctium lappa L. extract were optimal. The fresh weight of spinach which treated by 500 mg/L Arctium lappa L. extract were optimal, but no significant difference in fresh weight occurred between 30 mg/L and 500 mg/L. Therefore, the appropriate concentration of Arctium lappa L.extract was 30 mg/L when considering spinach's growth, quality and the cost of Arctium lappa L. extract.