Objective Establishment of orthotopic transplantation tumor model of human choriocarcinoma in nude mice.   Methods Human choriocarcinoma cell line JAR was cultured and the single cell suspension was subcutaneously injected into five 8-week-old BALB/c nude mice to establish subcutaneous xenograft model. After subcutaneous tumor was formed in nude mice, the tumor tissue was taken under aseptic conditions and cut into 1 mm³ tissue blocks, and then implanted into the uterine cavity of ten 10-week-old BALB/c nude mice by surgery. The nude mice were anesthetized and killed by anesthesia, and the uterine tumor formation and abdominal metastasis were observed. Anatomical uterine orthotopic transplantation tumors, intra-abdominal metastases, abdominal lymph nodes and other organ tissues were dissected and identified by histopathological examination.   Results A total of 7 nude mice in 10 BALB/c nude mice showed a tumor mass formation in the uterus, and 2 of them could simultaneously observe uterine xenografts and peritoneal metastasis. The pathological morphology and structure of the tumor cells in the subcutaneous xenograft model, orthotopic transplantation model and peritoneal metastasis were consistent with the human choriocarcinoma cancer cell line JAR.   Conclusion  The BALB/c nude mice orthotopic transplantation model of human choriocarcinoma JAR cells was successfully established.