Anterior mediastinal inflammatory myofibroblastoma is a rare tumor with insidious onset and easy misdiagnosis. In this report, we presented a case of anterior mediastinal inflammatory myofibroblastoma with thymoma. The mediastinal tumor was found by physical examination, and the prognosis was good after surgical treatment. For this disease, operation is an effective method for definite diagnosis and treatment, and complete excision can achieve good outcomes.