Objective To evaluate the cure and effect in the treatment of ureteropelvic junction obstrution(UPJO)by dismembered pyeloplasty.Methods Clinical data of 21 cases with ureteropelvic junction obstruction were reviewed who were treated by dismembered pyeloplasty.Results 20 cases gained success by one operation.1 case had ureteropelvic junction(UPJ)stenosis,which was cured by a second operation.1 case had renal function prostration before operation,which was improved after operation.15 of 21 cases had been followed up and their hydronephrosis was improved and their UPJ became unobstructed.Conclusion Dismembered pyeloplasty is effective in the treatment of UPJO.