Rib-diaphragm angle is the iconic position on the radiographs when taking chest orthopantomograms, referring to the angle between the ribs and the diaphragm, which is normally at an acute angle and is relatively clear. Bilateral rib diaphragm angle sharp suggests that bilateral rib diaphragm angle is normal, indicating that there is no accumulation of blood and fluid between the rib diaphragm angle, no pleural tissue adhesion and other lesions, do not need special treatment do not have to be too nervous. If chest trauma occurs, there is bleeding in the chest and blood will accumulate in the rib diaphragm angle, resulting in the loss of the local sharp angle. In case of lung infection and pleurisy, there will be obvious accumulation of pleural fluid in the angle of the rib-diaphragm, leading to rounding of the angle of the rib-diaphragm and the occurrence of pleural adhesions. Depending on the cause of the disease, hemostatic or anti-infective treatment should be given, and the results of treatment should be reviewed with chest radiographs or chest CT.