Hydrothorax and abdominal fluid should be based on the patient’s medical history, physical examination, as well as thoracic and abdominal ultrasound, thoracic and abdominal CT, cardiac ultrasound, a variety of blood tests and examinations, to clarify the cause of hydrothorax and abdominal fluid, whether it is caused by cardiac disease, caused by liver disease, or renal disease, and then make the next step in the management of the diagnosis after the clarification of the diagnosis. If the patient’s hydrothorax is caused by the heart, cardiotonic, diuretic, potassium supplementation treatment can be given, and must be directed by a professional physician. If the hydrothorax is caused by liver, it can be given protein supplementation, hepatoprotection treatment, after gastroenterology or hepatology doctor treatment advice, if it is caused by nephrotic syndrome, hormone treatment can be applied, the specific method adopts the treatment plan of nephrology. It may also be malignant pleural fluid caused by thoracic and abdominal tumors.