Cytochrome P450(CYP)is one of the main hepatic metabolic enzymes of phase I.Cytochrome P450 2E1,one member of CYP family,plays a significant role in the metabolism activation of chemicals,and its activity is strongly related to the final toxicity of chemicals.In the past years,many experts have put much endeavor to tackle this troublesome problem.This paper reviewed the progress of CYP2E1 activity assay in recent years.