In recent years, heavy metal pollution has become increasingly serious. Tegillarca granosa lives in a certain water body for a long time. Because of its poor movement ability, it is prone to heavy metal poisoning, especially cadmium poisoning. At present, the researches on Cd stress of T. granosa mainly focus on the bioaccumulation kinetics, acute toxicity and immune response of T. granosa to Cd, most of them are unilateral researches, and few of them are studied together. Therefore, this experiment studied the accumulation of cadmium, the changes of related enzyme activities and the effect on gene expression level after water treatment with cadmium concentrations of 0, 0.05, 0.1 and 0.5 mg/L respectively. The results showed that the content of cadmium in T. granosa increased significantly under the stress of cadmium, and the changes of cadmium content presented obvious time-dose effect. After cadmium stress, the content of cadmium in the gills and mantle was significantly higher in the 0.05 and 0.1 mg/L groups than in other tissues, and the content of cadmium in the visceral mass was the highest in the 0.5 mg/L group. SOD and ATPase activities and MDA contents in T. granosa liver and pancreas tissues under cadmium stress showed an upward trend in the early stage and a downward trend in the later stage, and were all higher than those in the control group. Cd stress up-regulated the transcription levels of ABCA3, SOD and MT genes. The results show that the increase of cadmium content can cause the changes of enzyme activity and related gene expression, and the changes of the relationship between the three can provide basic data for the molecular ecotoxicology study of beach shellfish.