Objective:To explore the hemodynamic and comfort effect of modified prone-flexed position in complexity renal calculi patients undergoing percutaneous nephrolithotomy.Methods:A total of 82 cases of complexity renal calculi patients who undergoing percutaneous nephrolithotomy were recruited and randomly assigned to experiment group (41 cases) and control group (41 cases). Patients in the control group were placed in conventional prone position, while in the experiment group were placed in modified prone-flexed position. The data include blood pressure, heart rate, respiratory rate, saturation of blood oxygen were recorded at preoprative, lithotomy position, change position 30 minutes after operation and postoperative. The General Comfort Questionnaire (GCQ) score was recorded in patients for postural comfort. The clinical data was also compared between two groups.Results:There was no significant difference in blood pressure, heart rate, respiratory rate, saturation of blood oxygen between experiment group and control group ( P>0.05). Compared to (44.95±4.80) min, 90.2% (37/41) of the control group, the patients in the experiment group was (47.80±6.71) min, 73.2% (30/41), which showed a shorter average operation time and higher total stone clearance rate, the differences were statically significant ( tvalue was 2.216, χ2value was 3.998, P<0.05). At immediately and 30 minutes after operation, the skin pressure were 9 cases and 4 cases in the experiment group, 18 cases and 11 cases in the control group, the differences were statically significant ( Zvalues were 2.132, 2.038, P<0.05). After 48 hours of surgery, the physical subscale and totl GCQ score were (13.32±1.40) and (78.56±4.65) pionts in the experiment group, significantly higher than (12.17±1.41), (75.76±5.16) pionts in the control group, the differences were statically significant ( tvalues were 3.685, 2.584, P<0.01 or 0.05). Conclusion:Modified prone-flexed position can shortern operation time decrease the risk of pressure injury and demonstrate better postural comfort of patients with complexity renal calculi undergoing percutaneous nephrolithotomy.