Iridoids,important active ingredient,are widely distributed in varieties of Chinese herbal medicines and have varieties of pharmacological activities,such as antitumor,anti-inflammatory,hypoglycemic and so on.It is generally recognized that the biological activity and mechanism of iridoids depended on their structures.At present,there is no reports on the summary of the structure modification and structure-activity relationship of iridoids,so it is very important and significant to summarize in details the structure and structure-activity relationship of iridoids for providing new ideas on the study of the structural activities of iridoids.In this review,the relationship between the chemical structure,biological activity,and the mechanism of iridoids by investigating literature research are analyzed and summarized in the world.It will be beneficial to the activity prediction and structure optimization of iridoids,and will provide a research basis for the new iridoid drugs with higher activity in the future.