Objective: To retrospectively analyze clinical data of patients under 40 years old who underwent surgical treatment for renal tumors with tumor thrombus from January 2016 to December 2022 at Peking University Third Hospital, and to evaluate the surgical effect and investigate the relationship between clinicopathological characteristics and prognosis. Methods: The clinical data of 17 young patients with renal tumor thrombus were retrospectively analyzed, and the clinicopathological features and prognosis were summarized. The patients were grouped according to the presence or absence of symptoms, 2017 American Joint Committee on Cancer (AJCC) clinical stage, and postoperative combined adjuvant therapy. Kaplan-Meier method was used to plot the survival curve, and Log-rank test was used to compare the differences in postoperative survival time and progression-free survival time between the different groups. The relationship between clinicopathological features and prognosis was analyzed. Results: All the 17 patients received venous tumor thrombectomy, including 16 patients (94.1%) who underwent radical nephrectomy and 1 patient (5.9%) who underwent partial nephrectomy. Twelve patients (70.6%) had symptoms and 5 (29.4%) had no symptoms before operation. A total of 17 renal tumors were observed, with 2 patients (11.8%) identified as benign and 15 patients (88.2%) classified as malignant. Among the malignant tumors, 1 patient (6.7%) was diagnosed as clear cell carcinoma, while the remaining 14 patients (93.3%) were categorized as non-clear cell carcinoma. In terms of tumor stage, 8 patients (53.3%) were classified as stage Ⅲ according to the AJCC classification, while 7 patients (46.7%) were categorized as stage Ⅳ. Additionally, 6 patients (40%) received multiple adjuvant therapy, while 9 patients (60%) did not undergo such treatment. The follow-up period ranged from 2 to 78 months, with a median follow-up of 41 months. During this time, 3 patients (20%) died. The median survival time after surgery was 39.0 (2.3, 77.8) months, and the progression-free survival time was 16.4 (2.3, 77.8) months. There was no significant difference in postoperative survival time and progression-free survival time among young patients with renal tumor with tumor thrombus, based on the presence of symptoms before surgery (P=0.307, P=0.302), clinical stage of AJCC (P=0.340, P=0.492), and postoperative adjuvant therapy (P=0.459, P=0.253) group. Conclusion: The pathological types of young patients with renal tumor with tumor thrombus are more complex and varied due to symptoms, and the proportion of non-clear cell carcinoma in malignant tumor with tumor thrombus is higher. Symptomatic and non-clear cell carcinoma may be potentially associated with poor prognosis. Surgical operation combined with adjuvant therapy is a relatively safe and effective treatment for young patients with renal tumor and tumor thrombus.