Abstract: In order to alleviate the damage of copper stress on tobacco seedlings, the effects of β-aminobutyric acid(BABA) at different concentrations on the growth of seedlings, metabolism of reactive oxygen species(ROS) and copper ion transporter related-gene expression were investigated via experiments. The results showed that under 100 μmol/L copper stress, the root length and fresh weight of tobacco seedlings increased comparing with those of untreated seedlings. Under 0.5 mmol/L copper stress, 0.2 and 0.5 mmol/L BABA treatments decreased the contents of malonaldehyde(MDA) and hydrogen peroxide(H₂O₂), improved the activities of antioxidative enzymes(SOD, POD and APX), meanwhile the expression levels of NtNRAMP, NtYSL and NtPDR genes, which regulated the transportation of divalent metal ions in tobacco seedlings, significantly increased. It indicated that BABA alleviated the damage of tobacco caused by copper stress through regulating the antioxidant system and the expression levels of genes related to the transportation of metal ions.