Abstract: Objective: To explore the feasibility of iDose⁴ iterative reconstruction technique in low-dose chest CT scans of preschool children. Methods: One hundred and fifty patients underwent non-contrast chest CT examinations, they were randomly assigned into three groups: control group (standard dose protocol 120 k V, 50 mAs) (n=50); 25 mAs group (low dose protocol 120 k V, 25 mAs) (n=50); and 10 mAs group (low dose protocol 120 k V, 10 mAs) (n=50). Images from control group were reconstructed by FBP, and low-dose groups were reconstructed by FBP and iDose⁴. Subjective image quality was assessed by two associate chief physicians of radiology department in a blinded manner. Image quality and radiation dose of the 3 groups were compared and analyzed statistically. Results: Subjective and objective image quality in 25 mAs group with iDose⁴ compared with FBP was increased. Subjective and objective image quality in 10 mAs group with iDose⁴ compared with FBP was increased either. Subjective and objective image quality in 25 mAs with iDose⁴ was increased compared with control group. Subjective and objective image quality has no significant statistical difference between 10 mAs with iDose⁴ and control group. Effective dose in low dose groups 50 mAs and 25 mAs was decreased by 52.6% and 78.2% respectively. Conclusions: 50 and 25 mAs groups with iDose⁴ technique (iDose⁴-5) could obtain acceptable image quality in low-dose chest CT scans of preschool children while decreasing radiation dose.