Atmospheric deposition is the main source of lead accumulation in the leafy vegetable crops, but the chemical speciation and oxidative stress of lead in Brassica chinensis L. under wet deposition have not been fully understood. In this study, the accumulation, subcellular distribution, chemical speciation of Pb and antioxidant response of Brassica chinensis L. by spraying different lead concentrations were investigated. The results indicated that the Pb concentrations in edible parts ranged from 1.72 to 6.35 mg/kg, which were in the range of 4.73-20.16 times above the standard (GB 2762-2017). Most of the Pb accumulated in the edible parts (>95%), while only a few (1.14%-3.11%) accumulated in the roots. The Pb in Brassica chinensis L was primarily distributed in the cell wall fraction, while the soluble fraction and organelle fraction accounted for a similar proportion. Oxalate and insoluble phosphate states were the main chemical speciation of Pb. The Pb concentrations in the leaves and stems cell wall accounted for 52.14%-86.99% of total accumulation, most of which were insoluble oxalate fractions, causing the high accumulation of Pb in the edible parts. The storage of large amounts of heavy metals in the cell wall, as well as the formation of less toxic oxalate and insoluble phosphate states, might be one of the important detoxification mechanisms of Brassica chinensis L. Wet deposition of Pb caused the oxidative cellular damage, increased malondialdehyde content in leaves and stems and inhibited chlorophyll synthesis, but it promoted the soluble sugars and soluble proteins. Brassica chinensis L. could effectively respond to wet deposition Pb stress by increasing the activity of antioxidant enzymes (superoxide dismutase, peroxidase, catalase)(7.73%-346.91%), as well as increasing the content of antioxidants (ascorbic acid, glutathione) and soluble substances (soluble sugars, soluble proteins)(9.11%-279.59%). The antioxidant enzyme activities had the biggest change in the leaves, increasing by 49.41%-91.62% and 123.42%-346.91% for peroxidase (POD) and catalase (CAT), respectively. While the most significant change of antioxidant occurred in the roots, accounting for 134.15%-182.93% and 238.78%-279.59% of total content for ascorbic acid (AsA) and glutathione (GSH), respectively. The possible main reason for Brassica chinensis L. leaves to alleviate oxidative stress were peroxidase, catalase, soluble sugars, soluble proteins and glutathione, because of the significant correlation between those and wet deposition Pb concentration (P<0.05). These results could improve our understanding of the distribution behavior of Pb in the vegetables, and provide a theoretical basis for the environmental risk assessment of crops in atmospheric heavy metal stress areas.