A review with 61 references Along with the rapid development of the drug research technol. and detection methods, many guidelines are introduced focusing on impurities or hazardous substances residual in drugs by various countries. According to the procedure as follows: establishing study target, developing impurities testing method, sample determination, overall evaluation, setting limit and control, the impurities may be evaluated whether to control in final products within the different factors, such as impurity sources, impurity harmfulness, removal difficulty from the final product, etc. Research progress in quality control of impurities or hazardous substances in drugs is summarized in this paper from above aspects.