Objective To explore the effect of low dose CT scanning technology combined with image reconstruction in diagnosis and treatment of urinary calculi. Methods Sixty patients with urinary calculi in our hospital from May 2014 to May 2015 were selected as the research objects, pathological results were used as the criterion. They were divided into routine dose group and low dose group, all underwent conventional dose and low dose CT scanning. Filtered back projection technique (FBP) and iterative reconstruction algorithm (IRIS) were used to reconstruction in low dose group. Detection rate of all stones, detection rate of kidney stones, detection rate of ureteral calculus in the two groups were compared and CT volume dose index (CTDIvol) of patients were recorded; pattern noise, noise-signal ratio of the images by different image reconstruction technology were compared. Results There was no significant difference in detection rate of all stones, detection rate of kidney stones, detection rate of ureteral calculus btween low dose group (96.67%, 93.75%, 100.00%) and routine dose group (100.00%, 100.00%, 100.00%) (P>0.05). Average CTDIvol of routine dose group was (18.56±3.72)mGy, low dose group was (2.91±0.34)mGy, the radiation dose of the latter was decreased 84% compared to the former(P<0.05). Average noise of low dose IRIS algorithm image was significantly lower than FBP algorithm image while the average noise-signal ratio was significantly higher than it (P<0.05). Conclusion Low dose CT scanning technology combined with IRIS to reconstruct image can ensure quality of image. The detection rate of urinary calculi has no significant difference from detection rate of conventional dose, can be used in diagnosis of urinary calculi.