A hydroponical culture experiment of Iris lactea was conducted to explore responses of the plants to NaCl and NaHCO₃ stress(0,70,210,350 mmol L^-1) for 10 days in plant growth,water status,cell membrane permeability,chlorophyll content and photosynthetic characteristics.Results indicate that Treatments NaHCO₃ were much higher than Treatments NaCl,the same in Na⁺ concentration,in effect inhabiting growth,decreasing water content,damaging cell membrane permeability and reducing chlorophyll content,which may probably be attributed to the combinative effect of high pH and high salinity in the former.Meanwhile,under alkali-saline stress,plant shoots were affected more than roots,and plant fresh biomass decreased more than dry biomass.Plant chlorophyll content decreased with increasing stress concentration and duration of the stress.Plant electrolyte leakage was negatively correlated to water content in leaves.Non-stomatal restriction was the main cause for reduced plant photosynthetic rate under NaHCO₃ stress,while under NaCl stress,both stomatal restriction and non-stomatal restriction occurred.