Abstract: Inositol requiring enzyme 1 alpha (IRE1α), a widespread transmembrane protein in mammals, is an endoplasmic reticulum stress (ER stress) receptor. Among the three signaling pathways of the unfolded protein response (UPR), the IRE1α pathway is the most conservative. And there is a growing body of evidence that the occurrence and development of tumors is closely related to the over-expression of IRE1α. Therefore, the study of the IRE1α inhibitors is of great significance to the discovery of new anti-tumor drugs and has been attracting more and more attention. In the hope of providing ideas for the research of targeting IRE1α for cancer therapy, this paper reviewed the data of representative IRE1α inhibitors, including inhibitory activity, the mechanism of action, structural characteristics, and so on.