Abstract: Objective:To explore the value of MSCT in children's tracheobronchial microdose. Methods:528 children with tracheobronchial bronchi in recent 3 years were collected. The effective radiation doses of 5 age groups, including low dose group, micro dose group and micro dose combined iterative reconstruction technology group, were compared and analyzed, and the reconstruction image of bronchial tree was obtained by post-processing technology to observe the diagnostic effect. Results:there was no significant difference in image quality evaluation between the three groups in different age groups(P>0.05), except for the difference between the low-dose group and the microdose group in the age group of 10-14 years old(P>0.05), there was significant difference in effective radiation dose in other age groups(P<0.05). There were 356 cases(67.4%) of type Ⅰ, 198 cases(37.5%) of type Ⅰ A, 158 cases(29.9%) of type Ⅰ B and 172 cases(32.6%) of type Ⅱ. Conclusion:Micro dose MSCT combined with iterative reconstruction technology can significantly reduce the effective radiation dose in the diagnosis of children's tracheobronchial bronchi, which has a high application value; effective typing has a certain specific guiding role in the clinical treatment of Pediatrics.