In order to reveal the effects of different selenium(Se)sources and concentrations on physiological and biochemical characteristics of forage ramie seedlings，the pot experiment was conducted to study the difference between sodium selenite(Se4+)and sodium selenate(Se6+)，using zhongshi Ramie No.1 as the test material.Concentration(0，0.9，1.8，2.7 mg·kg-1)had significant effects on plant biomass，Se content，total Se accumulation，photosynthetic pigment content，antioxidant enzyme activity，superanion radical content and production rate，malondialdehyde(MDA)and soluble protein content of forage ramie were analyzed.The results showed that soil Se application significantly increased Se content and its total accumulation in ramie，and it gradually increased with the increase of the Se dose.The absorption of Se6+ on the above-ground of ramie was much higher than that of Se4+，among which the Se content of ramie leaves and stems under the treatment of 0.9 mg·kg-1 Se6+ was 71.9 times and 54 times of that under the treatment of the same concentration of Se4+.0.9 mg·kg-1 Se6+ treatment improved superoxide dismutase，peroxidase(POD)，glutathione peroxidase(GSH-PX)and glutathione reductase(GR)activity，but increased strongly super anion radical content and release amount，reduced significantly the contents of chlorophyll and carotenoid，and the overground dry matter of ramie seedling was reduced by 90.3%，while the ramie seedlings died when the dosage of Se6+ was 1.8 and 2.7 mg·kg-1.The biomass，CAT and GR enzyme activity of ramie were significantly affected by selenite at different concentrations.Compared with the control group，the activity of CAT and GR in 0.9，1.8 and 2.7 mg·kg-1 Se4+ treatments increased by 130.6% and 37.6%，41.5% and 131.4%，176.7% and 117.4%，respectively，but 2.7 mg·kg-1 Se4+ reduced the overground dry matter weight by 24.7%.In the early stage of application，Se4+ had no significant effect on photosynthetic pigment and soluble protein，but chlorophyll content and soluble protein content were significantly increased and chlorophyll a/b ratio was decreased in the late stage of application.Therefore，the effect of Se6+ on the physiological and biochemical characteristics of ramie is far greater than that of Se4+，which is more easy to migrate in the plant and has strong bioavailability which can cause damage to the plant.Without affecting the biomass of ramie，the application of 0.9 mg·kg-1 sodium selenite could significantly increase the Se content and total Se accumulation，and alleviate the senescence of ramie.