A case of primary renal synovial sarcoma with inferior vena cava tumor thrombus was reported.The male patient was 32 years old,presenting recurrent right abdominal pain.Preoperative CT scan revealed right renal cell carcinoma combined with inferior vena cava tumor thrombus.He underwent radical nephrectomy of the right kidney and removal of inferior vena cava tumor thrombus.After operation,the pathology suggested renal synovial sarcoma.The patient's genetic molecular pathology suggested a better prognosis treating by cyclophosphamide-related therapy and negative immune related genes.The patient underwent first-line chemotherapy with ifosfamide and epirubicin.One year later,the patient developed lung metastasis and was treated with a combination of pembrolizumab,arotinib,gemcitabine,and docetaxel.The patient achieved complete remission.It is suggested that genetic test may have a value in the adjuvant treatment for this malignant tumor.