Radiotherapy following breast conserving surgery is a standard treatment in early stage breast cancer, and tumor bed delineation is a very important part of radiotherapy. Traditionally, operative record, preoperative ultrasound, postoperative scar, clips and other conventional methods were used to contour tumor bed in clinical, but they still have many limitations. In recent years, there were some progress in tumor bed delineation of the new style of lumpectomy cavity filling, preoperative/postoperative MRI images with CT images and other new methods. It is expected to solve the lack of postoperative tumor bed delineation consensus and standard in the future.