Brachytherapy with 125I radioactive seed has the advantages of low dose-rate,comtinuous irradiation and repeated implantation to inhibit the replication of tumor cells,and the repeatable implantation.It has been widely used in the treatment for cervial cancer,and can also be applied to pelvic malignancies,including ovarian cancer,colorectal cancer,bladder cancer.Compared with external beam radiotherapy,it can improve the dose of target region to control tumor effectively.At the same time,it can protect the normal tissues and reduce the occurrence of complications.In this paper,we summarized the speciahy,function mechanism,complications and application status of radioactive 125I seed interstitial implantation in the treatment of pelvic malignancies.The application of three dimensional printing in brachytherapy with radioactive 125I seed was also introduced.This review can provide a reliable basis for future standardized seed implantation treatment for pelvic malignancies.