Objective: To investigate the clinical characteristics, diagnosis and treatment of renal cell carcinoma with urinary tract tumor thrombus. Methods: From January 1, 2015 to December 31, 2019, patients with renal cell carcinoma complicated with urinary tract tumor thrombus who were hospitalized in the Peking University Third Hospital and Beijing Friendship Hospital, Capital Medical University were retrospectively analyzed. Meanwhile, we reviewed the literature, and the reported patients of renal cell carcinoma with urinary tract tumor thrombus were also included in our study. The basic information, clinical manifestations, treatment, pathological characteristics and follow-ups of all the patients were analyzed. Results: In our study, 6 patients from the two hospitals and 16 patients from previous literature reports were included. There were 13 males and 9 females with an average age of 54.7 years (22-79 years). Fifteen patients had renal cell carcinoma on the left side, 6 on the right side, and 1 on the unknown side. Gross hematuria was the most common chief complaint, including 18 patients. One patient complained of weight loss, 1 patient complained of microscopic hematuria, and 1 patient was found by ultrasound examination. Tumor thrombus was classified as grade Ⅰ in 9 cases (the tumor embolus protruded into the renal pelvis, but did not reach the ureteropelvic junction), grade Ⅱ in 10 cases (the tumor embolus protruded into the ureter, but not into the bladder), and grade Ⅲ in 3 cases (the tumor embolus passed through the ureter and protruded into the bladder). Only 11 patients were diagnosed with renal cell carcinoma before operation. Radical nephrectomy was performed in 9 cases and nephroureterectomy in 12 cases. In pathological diagnosis, there were 15 cases of clear cell renal cell carcinoma, 1 case of papillary renal cell carcinoma, 1 case of chromophobe cell carcinoma, 1 case of mixed cell renal cell carcinoma, 4 cases of renal cell carcinoma with undetermined classification. Eleven patients were followed up for 3-31 months, and 3 patients had lung metastasis within 6 months. Conclusion: Renal cell carcinoma with urinary tract tumor thrombus is rare in clinic. It needs to be differentiated from renal pelvis carcinoma in diagnosis. The treatment principle can refer to general renal carcinoma. For locally advanced cases, complete resection is the best treatment, and its oncological prognosis needs more long-term and large-scale follow-up observation.