Objective To investigate the feasibility and safety of Sandwich Balloon Dilation for totally ultrasound guided percutaneous nephrolithotomy (PCNL) . Methods An 18G needle with length marker was used to puncture the target calyx under the guidance of ultrasound and the depth of percutaneous tract was defined. Then the length of balloon similar to tract depth was marked by marker pen. Sandwich Balloon Dilation: Balloon was indwelled along the zebra guidewire until the marker, and inflated with 20atm for 5 minutes; 20.8F renoscope combined with EMS lithotripsy were used for fragmentation; finally before the end of surgery balloon was used again to tamponade the percutaneous tract. Results Between June 2014 and October 2014, a total of 56 patients (32 males and 21 females) with the average age of 53y underwent PCNL. The average stone size was 2.4±0.4cm; BMI23.1±2.8 and hospitalization 7 days. The average hemoglobin and hematocrit before and after operation was 14.1±2.1 vs 13.3±2.1g/dl and 40.7±5.3% vs 38.1±5.1%, respectively. No patient needed transfusion or embolization. No other severe complications happened. Conclusion Balloon dilation makes totally ultrasound PCNL easy and safe; while Sandwich Balloon Dilation further decreases haemorrhage complication.