Objective:To investigate the effect of potassium sodium hydrogen citrate in the treatment of renal uric acid calculi with heavy load.Methods:The clinical data of 6 patients with intrarenal high-load uric acid calculi (long diameter >4 cm) treated with potassium sodium hydrogen citrate in our hospital from January 2018 to July 2020 were reviewed. All of the patients were male. Their ages ranged from 42 to 66 years, with an average age of 51.3 years old. The average length to diameter was 6.0(4.1-7.6) cm. The average density of stone was 475 (418-535) HU. The average blood uric acid was 453.3(258.7-570.0)μmol/L, and all patients had a urine pH ≤5.5. The blood uric acid level was higher than normal serum uric acid level before treatment, and 3 cases had a history of gout. Stone composition analysis revealed 100% uric acid stone in two patients before treatment. The remaining patients were more likely to have uric acid calculi before treatment. None of the patients had a history of urinary tract infection. All patients were treated with oral potassium sodium hydrogen citrate. During the treatment, the starting dose was 10g/ day, which was divided into 2.5 g after breakfast, 2.5 g after lunch and 5.0 g after dinner. The dose was adjusted according to the pH value of urine, and the urine pH was maintained between 6.5-7.0. CT plain scan was repeated every 2-3 months during the treatment period to evaluate the treatment effect.Result:After 2.5-8.0 months’ treatment, the stone load of all the patients was reduced to different degrees, and the average length diameter was shortened by 3.2cm, among which two patients’ stones disappeared. CT scan showed the stone edge changed from smooth to rough after the treatment, and there would be worm erosion defect and cavity on the surface and inside of the stone, showing obvious stone dissolution phenomenon.Conclusions:Potassium sodium hydrogen citrate has a good therapeutic effect on renal uric acid calculi with heavy load. Non-infected patients with uric acid calculi should be treated with potassium sodium hydrogen citrate.