Objective To investigate the value in evaluation before microtrauma PCNL operation for complex renal stone patients who took the renal collecting system and renal artery joint image-forming technology of CT. Methods Divided patients of complex renal stone who took the microtrauma PCNL into 2 groups: test group:40 cases,except the conventional examination before operation,we still took the CT examination with the joint image-forming technology of renal collecting system and renal artery; contrast group:40 cases, only did the conventional examination before operation. To compare two groups’operation time, stone clearance rate and the incidence rate of serious complication. Results operation time of test group and contrast group is (75±30)min, (100±30)min,stone clearance rate is 90%, 82.5%,both groups’ incidence rate of serious complication is 0, 5%; Conclusion Renal collecting system and renal artery joint image-forming technology of CT can be clear to display anatomy relationship among stone, renal collecting system and renal artery,it has very important clinical significance in shortening time of complex renal stone’s microtrauma operation, raise the clearance rate and reduce the incidence rate of serious complication.