Objective To explore the value of CT lymphangiography(CTL)in the diagnosis of primary chylothorax.Methods The clinical and imaging data of 65 patients diagnosed with primary chylothorax were retrospectively analyzed,and all patients underwent direct lymphangiography(DLG)and CTL to analyze the abnormal deposition and reflux of the contrast agent and the morphological abnormalities of the lymphatic vessels.Results The sites of abnormal iodine oil deposition after CT lymphangiography in 65 patients were as follows:left thoracic cavity in 6 cases,right thoracic cavity in 2 cases,bilateral thoracic cavity in 6 cases,left subpleural cavity in 6 cases,right subpleural cavity in 5 cases,bilateral sub-pleural cavity in 4 cases,left thoracic wall in 3 cases,right thoracic wall in 1 case,bilateral posterior thoracic wall in 1 case,pulmonary hilum in 7 cases,lung in 10 cases,peripericardium in 4 cases,peribronchiovascular bundles in 3 cases,left bron-chiolo-mediastinal trunk in 1 case,and 1 case of double bronchial mediastinal trunk,1 case of left jugular trunk,22 cases of left jugular venous angle area,3 cases of double jugular venous angle,1 case of bilateral subclavian trunk,3 cases of left ax-illa,3 cases of double axilla,37 cases of mediastinum,13 cases of main thoracic duct and 2 cases of right lymphatic duct.Conclusion Abnormal distribution of contrast agent in CTL in the lungs,lymphatic conduits and lymphatic trunks is an im-portant manifestation of primary chylothorax,suggesting the abnormal distribution and severity of the thoracic organs,lym-phatic conduits and lymphatic trunks,and providing more imaging basis for the diagnosis and treatment of primary chylotho-rax.