ObjectiveTo discuss the diagnostic value of multi-slice spiral CT for bronchial mucoid impaction in early central-type carcinoma of lung. MethodsWe used multi-planar reformat, maximum intensity projection and minimum intensity projection to observe the characteristics of 15 patients with bronchial mucoid impaction in early central-type carcinoma of lung treated between March 2010 and October 2013. The characteristics included location, shape and enhanced performance of the tumor and the bronchial mucoid impaction. All the cases were confi rmed by operation or pathology. ResultsAmong the 15 cases, 12 were squamous cell carcinoma and 3 adenocarcinoma; 8 occurred on the right and 7 on the left. All the tumors showed equal density and were enhanced moderately. Bronchial mucoid impaction showed low density, no enhancement, accompanied bronchiectasis and occurred in bronchi which were far from the tumor, and there were 9 cases of strip, 5 of fabrication, and 1 of nodositas or cystic carcinoma. ConclusionThe location and shape of tumor and bronchial mucoid impaction are displayed clearly by multi-slice spiral CT and enhancement scanning can differentiate tumor from bronchial mucoid impaction. Multi-slice spiral CT has important diagnostic value in bronchial mucoid impaction of primary lung cancer in its early stage.