Abstract: Most chemical carcinogens,after intake,or after metabolic activation,can form covalent modifications of DNA(DNA adducts).DNA adducts formation induced by carcinogenic chemicals reflects exposure and is directly related to tumor formation.DNA adduct is a valid indicator of early key stage of carcinogenesis.Accelarator mass spectrometry (AMS) is a relatively new nuclear technique,has been developed for the detection of DNA adduct with great detection sensitivity.This powerful application allows studying molecular effects at the low-dose carcinogen exposure.