Primary mediastinal choriocarcinoma is a very rare malignant tumor unrelated to pregnancy. Here a case of primary mediastinal choriocarcinoma was reported. The patient was a 13-year-old boy. He presented with shortness of breath, chest pain, fever, irritable cough and weight loss. The imaging examination showed a huge space-occupying lesion at the right edge of mediastinum. The autopsy results showed right lung and mediastinal choriocarcinoma cell carcinoma. After the introduction of the case, this paper reviewed the clinical characteristics, diagnosis and treatment of primary mediastinal choriocarcinoma.