Objective To investigate the reasons for missed diagnoses of children's chest complex fractures in chest radiographs and to discuss the value of multi-slice spiral CT (MSCT) reconstruction in the diagnosis of children's chest complex fractures. Methods 123 children underwent chest digital radiography(DR) and MSCT scans after traumas were collected in our hospital between January 2012 and August 2015. This population consisted of 81 male and 42 female patients, with a mean age of 4.3 years(range from 9 months to 15 years). All participants underwent chest MSCT scans in 1-3 days after completing chest DR, and then we used 3D reconstruction to process the data and compared the results with those processed by DR. Results By chest DR tests we identified 39 cases (61 places) out of 123 participants with 24 simple fractures, 15 complex fractures. And 48 chest fractures were suspected. We also identified 36 cases had chest complications without fracture. By MSCT scans 76 cases (142 places) were identified, among which 42 were simple and 34 were complex. Compared with chest DR, MSCT scans can identified 18 more places of simple fractures and 63 more places of complex fractures. It was statistically significant higher detection rate of MSCT scan than DR. Conclusion Chest MSCT scan combined 3D reconstruction technology can increase the detection rate of chest complex fracture. Compared with DR, it provides more detailed and visualized information, including fracture position, type, severity and adjacent structure damage. It has important guiding value on the selection of therapy and prognosis evaluation.