Abstract: The high quality of crude drug is the key to the source and controlling of drug quality. Research and control impurities of crude drug is not only the key elements of quality guarantee, but also is the important evaluation indexes of ensuring drug safety and controllability. In this paper, related progesses in rencent years were summarized, including the classification and analysis method of impurities and so on. This paper also expounds the importance of crude duge impurities in the inspection and control, it is practical value for drug research, production, storage, transportation and other links to ensure that the drug is safe and effective.