When pleural effusion occurs after resection of left lobe of liver cancer, consider malnutrition, infection, tumor metastasis, etc. According to the amount of pleural effusion, take symptomatic treatments such as diuresis, extraction of pleural fluid (fluid staying in the thoracic cavity), supplementation of nutrition, etc. for treatment. 1. When the amount of fluid is small: the body becomes weak after surgery, which causes the reduction of albumin and leads to the production of pleural effusion, at this time, treatment should be actively carried out through diuresis (e.g. oral spironolactone, furosemide, etc.), supplementation of albumin, fresh frozen plasma and other treatments. 2. When the amount of fluid is high: considering that the stimulation of chest cavity and lungs after liver cancer surgery leads to lung infection, thus resulting in pleural effusion, on one hand, antibiotics (e.g. cefoperazone, moxifloxacin, etc.) should be used to control the infection, and on the other hand, chest puncture should be actively used to drain the pleural fluid for treatment. And supplement albumin, etc. as appropriate. 3. In addition, if diagnosed with tumor metastasis, in addition to the above treatment plans, targeted therapy (sorafenib, lenvatinib, etc.), chemotherapy (cisplatin, fluorouracil, etc.), radiotherapy and other treatments are also needed. After liver cancer resection, wound care, diet and activities should be carried out according to doctor’s instructions, and any abnormality should be reported to medical personnel immediately.