Chest fluid accumulation after lung cancer surgery may be caused by infection, postoperative blood seepage and hypoproteinemia, which need to be treated with drainage and observation, anti-infection, protein supplementation and diuresis. 1. Postoperative blood seepage, lung cancer will damage normal tissues, and a small amount of seepage will appear after surgery, which will lead to fluid retention in chest, usually the amount is not very large, and it can be drained through the drainage tube left after surgery and can be absorbed by human body naturally, most of them don’t need to have special treatment, and it is enough to take good care of the patient and monitor his/her condition. 2. Infection, postoperative hygiene is not done, resulting in infection may also appear in the chest fluid, accompanied by chest tightness, chest pain, need to carry out bacterial culture, and then according to the results of the use of cefepime, levofloxacin and other antibiotic treatment. 3. Postoperative patients are weak and have obvious hypoproteinemia, which leads to the leakage of intravascular fluid into the pleural cavity, resulting in fluid in the chest, if necessary, human albumin infusion is given to correct the hypoproteinemia, and diuretic medication is given in moderation to reduce the accumulation of fluid in the chest.