Objective Thymoma is associated with autoimmune diseases. We retrospectively analyzed the clinical characteristics of thymoma complicated systemic lupus erythematosus (SLE). Methods Patients were from Qilu Hospital Shandong University between June 2004 and June 2014, and satisfied classification criteria of American College of Rheumatology (ACR) classification criteria 1997 for SLE. Thymoma was diagnosed by chest CT scan. Results Nine cases were of thymoma complicated with SLE, with the male:female ratio of 1∶8. The age of SLE onset was (48±19) years, age of thymoma discovery was (47±19) years. The follow-up period was 3 to 10 years. Three cases (33%) were benign thymoma and underwent thymectomy and verified by histopa-thology test. One case presented thymoma 9 years after SLE, 5 cases (56%) presented SLE and thymoma simultaneously, 3 cases (33%) presented SLE after thymectomy. Clinical manifestations of SLE included 4(44%) skin lesions, 8(89%) polyarthritis, 5(56%) nephritis, 3(33%) leukocytopenia, 3(33%) throm-bocytopenia, 2 (22%) of interstitial pneumonia, 4 (44%) pleural effusion, no neuropsychiatric systemic lupus erythematosus. Nine cases (100%) were ANA positive, 7 (78%) were anti-dsDNA positive. Conclusion SLE complicated thymoma usually occurs in relatively older age, tend to present with multi-systemic presentations, and high percentage of anti-dsDNA positivity.