Strontium-induced stress in growth and chlorophyll contents ofPlatymonas subcordiformis was investigated under laboratory condition. The results showed that strontium exposure had little influences in general on growth and chlorophyll contents of the algae except for very high Sr concentrations.The maximum biosorption capacity of strontium ranged from 69.62 to 269.18 mg Sr2+/gdry weight. The algal biomass exhibited high uptake capacity of strontium. Total superoxide dismutase (SOD) activity and the content of lipid peroxidation products malondialdehyde (MDA) were significantly different in different treatments. SOD activity reached the highest level at 0.09 mmol/L that was about 55.8 % higher than that in the control. The MDA content increased significantly at 0.36 mmol/L, which was 2.15 times higher than that in the control, indicating a state of oxidative stress. With the increase of strontium concentration,the amount of fatty acids decreased.