The causes of gallbladder cancer, liver cancer pleural and abdominal fluid include hypoproteinemia, portal hypertension, thoracic and abdominal implantation metastasis and so on. 1. Hypoproteinemia, with liver cancer and gallbladder cancer, the ability of liver to synthesize albumin decreases, hypoproteinemia occurs, plasma colloid osmotic pressure decreases, so that fluid in blood vessels enters into the abdominal cavity to form ascites. 2. Portal hypertension, increased pressure of hepatic sinusoids, increased generation of hepatic lymphatic fluid, leakage from hepatic peritoneum into the abdominal cavity and formation of ascites. In addition, increased portal venous pressure, visceral vascular bed hydrostatic pressure increases, prompting fluid into the tissue space. 3. Thoracic and abdominal implantation metastasis, most of the patients with malignant tumors with hydrothorax and ascites indicate that thoracic or abdominal metastasis has occurred. Cancer cells invade into the thoracic and abdominal cavities, causing increase in the permeability of blood vessels, and the fluid leaks out to the thoracic and abdominal cavities, which leads to abnormal increase in the fluid in the thoracic and abdominal cavities. A small amount of thoracic and abdominal fluid can be naturally absorbed by the body, but a large amount of thoracic and abdominal fluid will cause respiratory and circulatory disorders, and in serious cases, even jeopardize the patient’s life. Patients with liver cancer and gallbladder cancer, who have chest and abdominal fluid, need to go to the hospital for diagnosis, clarifying the nature of ascites and timely treatment.