Objective:To observe the clinical effects and mechanism of “Qingli Huayu Xiaoshi Decoction” on pyelic stones  Methods:80 cases of pyelic stones were randomly divided into treatment group and control group, and 40 patients in each group. Patients in treatment group were given “Qingli Huayu Xiaoshi Decoction”, while patients in control group were given Pai Shi Ke Li for 6 weeks. Treatment efficacy and levels of urinary calcium and uric acid were calculated and analyzed  Results:Cure rate of treatment group was 87.5% and total effective rate was 95.0%; Cure rate of control group was 37.5% and total effective rate was 72.5%; compared with control group, treatment group achieved much higher cure rate(P<0.01). After treatment, urinary calcium and uric acid of treatment group decreased significantly (P<0.05,P<0.01), while urinary calcium of control group decreased after the treatment(P<0.05)；and urinary calcium and uric acid of treatment group were lower than control group(P<0.05)  Conclusion:“Qingli Huayu Xiaoshi Decoction” could efficiently and safely move renal stone, and the mechanism was related to decreasing urine calcium level and urine uric acid level.