Chylous pericardial effusion is a rarely reported complication of lung cancer surgery. Here, we report a case of an elderly man who suffered chylous pericardial effusion after radical right upper lung resection for cancer. The massive chylous effusion first occurred in the pericardium, drained to the right chest after the drainage of the hydropericardium and subsequently moved back to the pericardium again. Lymphoscintigraphy examination indicated that a chylous fistula was present in the plane of the tracheal carina. After failure to control the chylous effusion with conservative medical treatment, the patient underwent video-assisted thoracic surgery through the left chest for thoracic duct ligation and pericardial fenestration. The patient was ultimately discharged without recurrence of the effusion after surgical treatment. This case report discusses the possible mechanism of chylopericardium after lung cancer surgery and suggests some strategies to prevent postoperative chylous pericardial effusion.