Soil-culture medium was used to investigate the physiological and ecological response of the Kandelia candel (L.) Druce to cadmium pollution stress, including the contents of tannin, soluble sugar and proline. The seedlings were cultured in greenhouse conditions under a series of cadmium pollution stress(0～50 mg•kg^-1) from the beginning of May in 2004 to the end of December in 2004. After harvesting, the contents of tannin, soluble sugar and proline of leaves in Kandelia candel (L.) Druce were measured. The results showed that contents of tannin, soluble sugar and proline all increased firstly in lower cadmium stress, which might be regarded as a self-protecting function of plants. After they reached the highest values, 66.2mg•g^-1, 105.0mg•g^-1 and 12.2mg•g^-1, when the treated concentration of CdCl2 was 30mg•kg-1, 20mg•kg^-1and 40mg•kg^-1, respectively, the contents of these solutes decreased. This indicates that the plants would have been harmed at the greater amount of cadmium. The increasing concentration of tannin might result in the over accumulation of cadmium in Kandelia candel (L.) Druce. As tannin can combine with cadmium, however, it could reduce the toxicity of this pollutant. The increasing concentration of soluble sugar and proline functioned as osmotic adjustors, so the heavy metal cadmium could be less harmful to the plant. As the content of proline was significantly influenced by the cadmium stress, it could provide a valuable monitoring index of heavy metal cadmium pollution.