The CT manifestation of chronic bronchitis is mainly increased and thickened texture of both lungs. If it is accompanied by acute attacks such as cough, sputum and fever, it is easy to show increased, thickened and disturbed texture of both lungs, even with a little patchy shadow. Therefore, in addition to the bronchial changes, the CT manifestation of chronic bronchial should also pay attention to whether it is combined with pulmonary fibrosis, bronchiectasis, pneumonia, tuberculosis, etc. The manifestations of chronic are mainly increased texture and thickening, while the manifestations of other diseases include patchiness, nodules, fibrosis, bronchial cystic and columnar dilatation, etc. Therefore, the CT manifestation of chronic bronchial is generally based on texture manifestation, which varies from mild to severe in combination with the history of bronchitis, and some patients with relatively short duration of bronchitis often have less obvious CT manifestation, which needs to be combined with clinical manifestation to make further diagnosis.