There are many reasons for hydroperitoneum after colon surgery, the common ones include concurrent infection, tumor cell metastasis, hypoalbuminemia, etc. It is necessary to define the cause of the disease and then standardize the treatment for the cause. 1. Complicated infection: After colon surgery, due to improper postoperative care and ineffective anti-infective treatment, bacterial infection may occur, and inflammation stimulates the peritoneal mucosa to appear inflammatory exudation, which will form ascites. 2. Tumor cell metastasis; if colon cancer is not completely removed from the lesion during operation, the residual tumor cells will be planted and metastasized in the abdominal cavity, which will easily form hydroperitoneum. 3. Hypoalbuminemia: after colon surgery, if the patients have poor physical quality, nutritional disorder will form hypoalbuminemia, and leakage of fluid will form peritoneal effusion. After colon surgery, abdominal fluid, should be timely consultation, improve the examination, clear diagnosis and follow the doctor’s instructions for treatment.