ObjectiveTo investigate the effect of minimally invasive percutaneous nephrolithotomy combined with flexible ureteroscope in the treatment of complex renal calculi and its influence on urokinase and renal function in patients.Methods From March 2014 to March 2017,82 patients with complex renal calculi treated in our hospital were enrolled in the study and grouped according to a random number table.In the control group (n=41),only minimally invasive percutaneous nephrolithotomy was used,while in the observation group(n=41),flexible ureteroscope was combined.The general conditions,serum creatinine,urokinase,and complications of the two groups were compared.ResultsThe hospital stay and operation time in the observation group were shorter,and the amount of bleeding was less compared with those in the control group,with statistical differences(P＜0.05).At the 7 day after treatment,the creatinine level was lower,while the urokinase was higher in the observation group than that in the control group,which were displayed statistical differences(P＜0.05).In the observation group,the removal rate of stone in one time was 92.68%,higher than that in the control group accounting for 73.17%,and the incidence of renal function injury was lower in the observation group (P＜0.05).Conclusion Combination of minimally invasive percutaneous nephrolithotomy and flexible ureteroscope obtains a significant effect on treating complex renal calculi,with a high removal rate,small trauma,and mild damage to renal function,which is worthy of promotion.