Objective To study the clinical value of retroperitoneoscope-assisted intraperitoneal approach in the treatment of large renal tumors.Methods A total of 89 patients with large renal tumors (d ＞7 cm) were involved from January 2014 to December 2017.Among them,32 cases were treated by retroperitoneoscope-assisted intraperitoneal approach (group A),including 18 males and 14 females,aged (63.5±7.5)years,with 20 cases on the left and 12 on the right,and mean tumor diameter of (7.9 ± 0.6).Thirty cases were treated by laparoscopy (group B),including 17 males and 13 females,aged (64.5 ±7.3)years,with 16 cases on the left and 14 cases on the right,and the average tumor diameter of (7.6 ±0.7) cm.Twenty-seven cases underwent open surgery (C group),including 15 males and 12 females,aged (64.9 ±5.7) years,with 13 cases on the left side and 14 cases on the right,and the average tumor diameter of (7.9 ±0.6) cm.There was no statistically significant difference among the three groups in term of demographics (P ＞ 0.05).The clinical data was collected and statistical analysis was made for comparison among the three groups,including operation time,blood loss,surgical complications,postoperative intestinal recovery and postoperative hospital stay.All the patients were with single renal tumor,and no other major comorbidities were found.Results All of the 89 surgeries were successful.Hypercapnia was found in 2 cases (6.3％) in Group A,and recoverd 15 minutes after stopping pneumoperitoneum and anesthesia.The operation time was 120-200 minutes with an average of (155.0 ± 22.1) minutes.The average amount of bleeding was (141.6 ± 33.8) ml.Bowel recovered 3 (3-5) days after operation.The patients were hospitalized for 7 (7-9) days.In group B,hypercapnia was found in 2 patients (6.7％) and recoverd after stopping pneumoperitoneum and anesthesia.The time of operation was (184.2 ± 20.6) min,the amount of bleeding was (191.5 ± 46.2) ml,the bowel recovered 4 (4-6) days after operation,and the postoperative hospitalization duration was 7.5 (6-9) days.The operation time of group C was (54.0 ± 16.6) min,blood loss was (309.6 ± 50.2) ml,postoperative intestinal recovery was 5 (4-6)days,and the postoperative hospitalization time was 8 (7-12)days.Group A had less operation time than Group B(P ＜0.05),and no difference with Group C(P ＞0.05).Group A had advantages in term of blood loss and postoperative intestinal recovery time compared with B and C (P ＜ 0.05).Groups A and B had no difference in term of surgical complications and postoperative hospital stay (P ＞ 0.05),but both of the two groups had obvious advantages over group C (P ＜ 0.05).Conclusions Retroperitoneoscopeassisted intraperitoneal approach is the synergetic application of two endoscopic approaches,which is superior to any single operation for the treatment of large renal tumor,such as less bleeding,shorter operation time,faster postoperative recovery,and so on.This method not only reduces the difficulty of operation,provides an alternative for laparoscopic treatment of large renal tumors,but also has a good application for complex renal tumors complicated with renal vein and inferior vena cava tumor thrombus.