Objective To evaluate the feasibility and efficacy of 125 I radioactive seed implantation in treat-ment of aggressive thymoma pleural metastases after surgical resection.Methods The clinical data of 16 patients with thymoma confirmed underwent surgery were retrospectively analyzed.All post -operative pleural metastasis were trea-ted by radioactive particle planting.Results No patients occurred serious complications.15 patients survived at the end of 12 months following -up,13 patients with complete or partial relieved,2 patients progressed and 1 patient lost to following -up.Conclusion DynaCT -guided 125 I radioactive seed implantation is effective and safe for treating aggressive thymoma pleural carcinomatosis,it offers a new and feasible treatment.