Objective To evaluate the diagnosis of ureteral stone by helical CT. Methods 25 patients with acute flank pain. hematuria and suspected of ureteral stone on B ultrasonography yet with negative,KUB and IVU underwent helical CT scanning. Results 24 cases were found to have ureteral stone by helical CT,the accurate rate being 96%.Three cases were fond to have Hydronephrosis,Ureteral dilation,Edema periureteric and secondary signs of ureteral obstraction. Conclusions Helical CT is safe,quick and accurate in diagnosing ureteral stone.