[Objective] The aim was to reveal the destructive effect of cadmium pollution on salt marsh plant from the perspective of physiological ecology,and to investigate the injured process and resistance mechanism of plant,in order to provide scientific basis for the ecotoxicology research on plants with heavy metal pollution.[Method] Taking Cyperus malaccensis L.as the test material,pot experiment was carried out to study the physiological response and resistance mechanism under cadmium stress.Plant height,diameter of aboveground stem,diameter of underground stem,fresh and dry weights of aboveground and underground parts were taken as the basic physiological indices.Leaf area,contents of chlorophyll a and b,soluble sugar and soluble protein,activities of CAT and POD were taken as biochemical indices.[Result] Low concentration of cadmium could promote the growth of Cyperus malaccensis L.,while high concentration of cadmium(≥5.0 mg/L) played an inhibitory role.Content of chlorophyll decreased with the increase of cadmium concentration,and cadmium stress had greater inhibited effect on chlorophyll a than chlorophyll b.The activity of root system and soluble protein content were improved under low cadmium concentration,and were inhibited under high cadmium concentration.Content of soluble sugar was on rise when cadmium concentration was smaller than 10.0 mg/L.The activity of CAT increased firstly and then decreased with the growth of cadmium concentration;while the activity of POD kept rising,which showed that when cadmium concentration was greater than 5.0 mg/L,the growth of Cyperus malaccensis L.was inhibited.[Conclusion] Cyperus malaccensis L.had realatively strong resistance. [Objective] The aim was to reveal the destructive effect of cadmium pollution on salt marsh plant from the perspective of physiological ecology, and to investigate the injured process and resistance mechanism of plant, in order to provide scientific basis for the ecotoxicology research on plants with heavy metal pollution. [Method] Taking Cyperus malaccensis L. as the test material, pot experiment was carried out to study the physiological response and resistance mechanism under cadmium stress. Plant height, diameter of aboveground stem, diameter of underground stem, fresh and dry weights of aboveground and underground parts were taken in the basic physiological indices. Leaf area, contents of chlorophyll a and b, soluble sugar and soluble protein, activities of CAT and POD were taken as biochemical indices. [Result] Low concentration of cadmium could promote the growth of Cyperus malaccensis L., while high concentration of cadmium (≥5.0 mg / L) played an inhibitory role. Content of chlorophyll decreas ed with the increase of cadmium concentration, and cadmium stress had greater inhibited effect on chlorophyll a than chlorophyll b. activity of root system and soluble protein content were improved under low cadmium concentration, and were inhibited under high cadmium concentration. Content of soluble sugar was on rise when cadmium concentration was smaller than 10.0 mg / L. The activity of CAT increased first and then decreased with the growth of cadmium concentration; while the activity of POD kept rising, which showed that when cadmium concentration was greater than 5.0 mg / L, the growth of Cyperus malaccensis L.was inhibited. [Conclusion] Cyperus malaccensis L.had realatively strong resistance.