Objective To evaluate the efficacy and safety of percutaneous nephrolithotomy(PCNL) by middle renal calice used as main access for the treatment of staghorn stones with the combination of pneumatic and ultrasonic lithotrite.Methods Clinical data of 73 patients underwent PCNL by middle renal calices as main access with 57 incomplete staghorn stones and 35 complete staghorn stones.The rate of stone removal and complications were the main points of the analysis.Results Seventy-two cases underwent first session PCNL by single access tract(middle calices),3 cases underwent first session PCNL by double access tracts (2 cases by middle and lower calices,1 case by upper and middle calices).Of these patients,1 case had fragments with no further treatment,16 cases underwent second session PCNL.All were treated by single access tract (middle calices) and 2 cases had extracorporeal shock wave lithotripsy before the second PCNL.Seventy-six cases composed of 27 complete staghorn stones and 49 incomplete staghorn stones had no residual fragments with the stones removal rate 82.6％ (76/92).Hemoglobin dropped 1-4 g/L,11 cases and 3 cases were given blood transfusion in the operation procedure and post operation respectively.One case developed pyelonephritis and 1 case had split renal dysfunction with peri-parenchyma infection.Conclusions By middle calices as a main access to perform PCNL for staghorn stones is effective and safe.Using pneumatic and ultrasonic lithotrite will be very useful with high stones free rate and short procedure time and less complication.