Optical coherency tomography (OCT) is one of the powerful optical imaging tools that allows cross-sectional tomography of the microstructure in living subjects with high resolution. With the rapid development of OCT and a wide range of preclinical and clinical tumor imaging, it provides profound insights into the complex physiological, cellular and molecular behaviors of tumors. Preclinical OCT has elucidated many inscrutable aspects of tumor biology, while clinical applications of OCT are revolutionizing diagnosis and therapies. As a new noninvasive optical imaging technique, OCT can realize the intraoperative imaging of tumor and provide meaningful image data, which will provide great help for the diagnosis, classification and boundary determination of tumor diseases in the future.