Abstract: Cadmium was one of the easiest accumulated environmental pollutants,and Chlamys nobills which belonged to the kind of shellfish in shallow sea and had significant bio-accumulation ability for Cd,was taken as an example to study the dietary intake risk scientifically and effectively.And then the method of in vitro digestion,which could simulate the physical and chemical environment of the gastrointestinal tract,was used to obtain the bioaccessibility of Cd in C.nobills for dietary intake.The result showed that the range of Cd bioaccessibility in C.nobills was from 36.5 to 63.3%(mean to 47.9%)and the main forms of Cd in chyme were MT-Cd and GSH-Cd.The Cd bioaccessibility of different tissues was in the order as sex gland(51.2%),adductor muscle(44.9%),viscera(40.6%)and gill lamella/mantle(37.4%).It also seemed that there was significant negative correlation between the mass fraction of sex gland and its bioaccessibility(R=-0.840,P<0.05),while a extremely significant positive correlation could be found between the mass fraction of visceral and its bioaccessibility(R=0.996,P<0.01).And the content of Cd in chyme mainly came from the tissue of gill lamella/mantle and adductor muscle(up to 63.5%).Because of the higher Cd contribution of viscera in the chyme than its corresponding mass fraction,the dietary intake risk of Cd might be reduced by a quarter if this tissue was removed before eating.