The effects of Si on the growth and Chromium accumulation of broccoli（Brassica oleracea L. var.italica Planc）seedlings under the different concentration of Chromium stress were studied with the method of K₂ Si O₃foliar spraying. The results showed that 50 mg·L^-1 Chromium stress promoted the growth of broccoli, which the seed-ling height, fresh weight per plant, SOD activity and POD activity increased and MDA content decreased. But theseedling height, fresh weight per plant, SOD activity and POD activity decreased and MDA content increased withthe chromium concentration increased when the chromium concentration was more than 100 mg·L^-1. Statistical analysis showed that the concentration of chromium which significantly affected the growth of broccoli was 100 mg·L^-1.The Cr⁶⁺ absorption in 1-100 mg·L^-1 Cr⁶⁺ treatments were promoted, but inhibited in 200 mg·L^-1 Cr⁶⁺ treatment. 1.5mmol·L^-1 K₂ Si O₃treatment could significantly promoted the seedling height, fresh weight per plant, SOD activityand POD activity of broccoli under the Chromium stress, inhibited the MDA content and chromium accumulationthereby reducing the poisoning of Chromium stress on broccoli.