Abstract: Objective Mixed cryptorchidism germ cell tumor is extremely rare in clinical practice. This paper aims to improve the comprehensive understanding of the disease，provide reasonable and effective treatment methods for the disease，and improve the survival rate. Methods The retrospective analysis was performed on the clinical data of 1 case of mixed cryptorchidism germ cell tumor confirmed by pathology，which contained 4 tumor components （seminoma about 50% + immature teratoma about 25% + yolk sac tumor about 20% + embryonal carcinoma about 5%）. Results The patient was admitted to hospital with“acute abdominal pain”，and the blood levels of AFP，HCG，and LDH were all elevated. Imaging examination showed space-occupying lesions in the abdominal cavity. The tumor and some surrounding tissues were surgically removed. After 6 months of follow-up， no tumor recurrence， and metastasis. Conclusion The treatment of mixed cryptorchidism germ cell tumor should be done as early as possible. Orchidopexy before the age of 2 can effectively reduce the occurrence of this disease. The treatment was radical resection combined with BEP （bleomycin， etoposide， cisplatin） chemotherapy. The prognosis varies according to the tumor components. The prognosis which contains choriocarcinoma is poor，while the seminoma is generally good.

Key words: cryptorchidism, mixed germ cell tumor, pathology, treatment, prognosis