Abstract:Methyl jasmonate (MeJA) with different concentrations (0,0.5, 1.0, 5.0, 10.0, 25.0 μmol?L-1) was applied by foliar spraying. Coreopsis was used as the experimental material and potted, the effects of MeJA on seed germination, seedling growth and antioxidant system of Coreopsis under cadmium stress were studied. A study has been undertaken to explore the effects of methyl jasmonate (MeJA) with various concentrations (0,0.5, 1.0, 5.0, 10.0, 25.0 micron ? l-1) on seed germination and seedling growth and antioxidant system of Coreopsis. Seeds were germinated on filter paper bedding and leaf spray of potted seedlings. The results showed that the growth of Coreopsis was severely inhibited when the cadmium ion concentration is 100 μmol?L-1. The application of MeJA (1.0 - 5.0 μmol?L-1) promoted the germination and increase the chlorophyll content of Coreopsis seedlings, promoted leaf dry matter accumulation and increase relative leaf water content, increased the activity of antioxidase, increased the content of oxidized glutathione and oxidized glutathione/reduced glutathione values, reduce the content of malondialdehyde and proline. That low concentration of MeJA could effectively alleviate the damage of Cadmium stress. However, high concentration of MeJA (above 10 μmol?L-1) exhibited inhibitory effects on the metabolism of Coreopsis seedlings. Overall, appropriate concentration of exogenous MeJA could promote the growth and cadmium tolerance of Coreopsis, through increasing decreasing osmotic adjustment substance contents, enhancing antioxidant enzyme activities, increasing GSH content and adjusting GSH/GSSG ratio.