Peritoneum is a layer of plasma membrane covering the surface of abdominal and pelvic organs, which will increase in thickness and change in structure after being stimulated by lesions, and the main causes of thickening include metastasis, mesothelioma, tuberculosis and peritonitis. 1. Metastasis: malignant tumors (ovarian cancer, gastric cancer, etc.) will have peritoneal implantation metastasis, and there will be peritoneal nodule-like and cake-like thickening, which can be found through examination of the primary lesion. 2. Mesothelioma: the peritoneum itself has mesothelial cells, and malignant transformation of mesothelial cells will directly lead to peritoneal thickening, which is closely related to long-term exposure to asbestos dust. 3. Tuberculosis: peritoneal tuberculosis is a form of extrapulmonary tuberculosis, after the appearance of peritoneal tuberculosis, it will lead to thickening of the peritoneum, which will cause a feeling of kneading and a series of symptoms related to the combination. 4. Peritonitis: it may be caused by bacterial infection, gastrointestinal perforation, intra-abdominal hemorrhage, etc. It belongs to the more serious surgical diseases, leading to nausea, vomiting, abdominal pain and other symptoms, and in severe cases, it may cause thickening of the peritoneum of the patient. Apparent thickening of the peritoneum, accompanied by significant abdominal pain and discomfort, the need for timely medical observation, to determine the specific causes of standardized treatment.