In order to study the effect of waterlogging stress on the growth and physiological metabolism of Astragalus sinicus L.，three cultivars(Yuganzhong，Minzi2 and Yijiangzi)were used as experimental materials.Waterlogging significantly reduced the biomass and plant height of three cultivars.Among three cultivars，the biomass of Yijiangzi under waterlogging showed the largest decline，reaching 38.1%.Under waterlogging stress，the biomass of shoot and root of Yijiangzi decreased by 34.8% and 40.1%，respectively，as compared with control.Under waterlogging stress，the maximum photochemical efficiency，electron transport efficiency and photochemical quenching coefficient of three tested cultivars decreased by 23.2% to 29.3%，8.3% to 14.8%，31.5% to 34.8%，respectively，and the non-photochemical quenching coefficient increased by 41.8%～70.8%.The photosynthetic activity of leaves was strongly inhibited by waterlogging.In addition，waterlogging resulted in a dramatic increase in the activity of antioxidant enzyme system，and the content of malondialdehyde in shoot were increased by 63.6% to 72.0%，and the content of malondialdehyde in root were increased by 52.4% to 63.1%.The catalase activity in the shoot of Yuganzhong，Minzi2 and Yijiangzi seedlings increased by 164.0%，127.1%，121.0%，the peroxidase activity increased by 30.4%，46.7%，30.7%，and the superoxide dismutase increased by 12.5%，10.2% and 15.0%，respectively.The fuzzy subordinate function analysis suggested that the waterlogging tolerance of three cultivars decreased in the order of Minzi2> Yuganzhong> Yijiangzi.