A field experiment of foliar application of silicon sol, cerium sol and silicon-cerium composite sol of different concentrations on cabbage in field mildly contaminated with cadmium and lead, was conducted to study effects of the application on yield, quality, antioxidant enzymes (SOD, POD) activities and Cd/Pb absorption, and hence to determine optimum concentration of the silicon sols and cerium sols to be sprayed for relieving toxicity of Cd and Pb. Results show that spraying both silicon and cerium sols could promote growth of cabbage, increase contents of vitamin C and soluble sugar; reduce nitrite content, enhance activities of SOD and POD, the antioxidant enzymes, and decrease contents and accumulation of Cd and Pb in root and shoot. In conclusion, among the treatments of silicon sols and cerium sols different in concentration, the one of 0.50 g kg^-1 (SiO₂) silicon sols and/or 0.20 g kg^-1 (CeO₂) cerium sols was the most significant in effect, but no significant difference was observed between the treatment of spraying one single sol and the treatment of spraying both sols in combination.