This paper deals with the impact of Hg²⁺, Cd²⁺ on chlorophyll contents and scarenging systems of activated oxygen in stems and leaves of Brasenia schreberi winter bud. The results indicate that, as increasing of the concentration of Hg²⁺ and Cd²⁺, chlorophyll contents, chlorophyll a/b values and soluble protein contents decreased, the activities of SOD and CAT increased first and decreased afterwards and the activity of POD increased from beginning to end. The results also show that Brasenia schreberi winter bud is more sensitive to Hg²⁺ than to Cd²⁺, its leaves is more sensitive than its stems.