COMET assay is a newly developed technology for detecting DNA damage on single cell level.Recently and after continues modification,the assay has been successfully modified to detect several DNA damages and become a sensitive biomarker.It also plays a more and more important role in identifying genotoxic substances from environmental sample,elucidating mechanisms of carcinogenicity,as well as biomonitoring environmental pollution.COMET technology has also been applied in environmental toxicology and risk assessment.In this paper,the origination and modification,environmental applications,and future trends are reviewed,for the benefits of utilization,data interpretation,and contributing to its further development by Chinese scientists.