Abstract: Objective: To investigate the effects of obesity on the clinical efficacy of percutaneous nephrolithotomy(PCNL).Methods:Ninety-eight patients treated with PCNL were divided into the control group and obesity group according to the body mass index.The clinical efficacy of two groups were compared.Results:There were not significantly statistical differences in the sex,age,blood loss,stone position,hospital stays,postoperative complication and anticoagulants use between the two groups(P0.05).The operative time in obesity group(82.46 12.79 min) was longer than that in control group(73.54 8.26min) (P0.01).The stone-free rate in obesity group(62.0%) was lower than that in control group(81.3%) (P0.05).Conclusions:The PCNL in obese patients is a safe and feasible method,but strengthening monitoring and postoperative residual stone processing should be pay more attention to.