Structural DNA nanotechnology enables DNA to be used as nanomaterials for novel nanostructure construction with unprecedented functionalities. Artificial DNA nanostructures can be designed and generated with precisely controlled features, resulting in its utility in bionanotechnological and biomedical applications. A tetrahedral DNA nanostructure (TDN), the most popular DNA nanostructure, with high stability and simple synthesis procedure, is a promising candidate as nanocarriers in drug delivery and bioimaging platforms, particularly in precision medicine as well as diagnosis for cancer therapy. Recent evidence collectively indicated that TDN successfully enhanced cancer therapeutic efficiency both in vitro and in vivo. Here, we summarize the development of TDN and highlight various aspects of TDN applications in cancer therapy based on previous reports, including anticancer drug loading, photodynamic therapy, therapeutic oligonucleotides, bioimaging platforms, and other molecules and discuss a perspective in opportunities and challenges for future TDN‐based nanomedicine.