In order to explore the effect of foliar selenium fertilizer on cadmium stress in lettuca sativa L.，the effects of different concentrations of foliar selenium fertilizer on cadmium accumulation in lettuce were studied by potting experiments. Two cadmium pollution concentrations(1 mg/kg，Cd1；3 mg/kg，Cd3)and three foliar selenium fertilizer concentrations (0 mg/L，Se0；1 mg/L，Se1；3 mg/L，Se3)were set up. The results showed that:①The spraying of foliar selenium fertilizer significantly reduced the uptake and accumulation of cadmium by lettuce，compared with the Cd1+Se0 and Cd3+Se0 treatments，and the cadmium content of lettuce leaves in Cd1+Se1 and Cd3+Se3 treatments was significantly reduced by 26.29% and 49.05%，respectively.②Spraying foliar selenium fertilizer at appropriate concentrations increased the activity of catalase(CAT)and superoxide dismutase(SOD)in lettuce，reduced the content of malondialdehyde(MDA)，and significantly reduced the MDA content of lettuce under Cd1+Se1 and Cd3+Se3 treatments by 44.48% and 48.90%，compared with Cd1+Se0 and Cd3+Se0 treatments，respectively. CAT and SOD under Cd1+Se1 treatment were more than Cd1+Se0 treatment by 40.38% and 68.71% respectively. And CAT and SOD under Cd3+Se3 treatment were more than Cd3+Se0 treatment by 77.48% and 51.70% respectively. Therefore，it can be seen that the spraying of foliar selenium fertilizer can significantly improve the stress resistance characteristics of lettuce，and then effectively inhibit the absorption of cadmium by lettuce. When the soil cadmium content is 1 mg/kg (Cd1)，the optimal foliar selenium fertilizer spray concentration is 1 mg/L，while when the soil cadmium content is 3 mg/kg (Cd3)，and the optimal foliar selenium fertilizer spray concentration is 3 mg/L.