Abstract: Objective To study the application value of low-dose multi-slice spiral computed tomography(MSCT)in the diagnosis of foreign body in children's bronchus. Methods A total of 80 children suspected of bronchogenic foreign bodies were selected as research objects, and were carried out MSCT examination. The result obtained was compared with those of bronchoscopy, and the diagnostic value of low-dose MSCT was analyzed. Results There were 72 cases diagnosed as bronchus foreign bodies by MSCT, of whom 22 cases were located in the trachea, 8 cases in the left main bronchus, 6 cases in the left lower lobar branch, 15 cases in the right main bronchus, 8 cases in the right middle segment and 13 cases in the right lower lobar bronchus. There were 3 false positive patients diagnosed by MSCT compared with bronchoscopy, and the rest of diagnosed patients were in accordance with bronchoscopic results, but there was no significant difference(P>0.05). MSCT visual display the location and shape of the foreign body, and can clearly reveal the secondary signs of emphysema, pneumonia, atelectasis and pneumomediastinum caused by foreign body incarceration. Conclusion Low dose MSCT can display the position, size and shape of foreign body in children's bronchus in all-round way in the diagnosis of foreign body in bronchus. It has the advantages of rapid scanning and accurate diagnosis as well as clear demonstration of indirect sign of a foreign body.