Malignant tumor-associated acute abdomen refers to a non-perioperative acute abdominal disease caused by malignant tumors or caused by various anti-tumor treatments with acute abdominal pain as the main clinical manifestation. It is often critical and even life-threatening. For patients with malignant tumor-associated acute abdomen, the occurrence and development of tumors and the evolution of acute complications are often causal to each other. Therefore, diagnosis and treatment of malignant tumor-associated acute abdomen usually require the surgery-based multidisciplinary treatment (MDT). According to imaging features and access to medical resources, oncologists and surgeons, working with other relevant professional teams need to develop the most appropriate treatment strategy through hierarchical management based on different oncology assessments and treatment goals. Yet there is no consensus on diagnosis and treatment of malignant tumor-associated acute abdomen. Therefore, Chinese College of Surgeons, Chinese Society for Clinical Oncologists, Chinese Society of Multidisciplinary Team, and the Chinese Journal of Gastrointestinal Surgery gathered multidisciplinary experts in China to discuss and develop the Chinese expert consensus on multidisciplinary management of malignant tumor-associated acute abdomen. This consensus consists of three parts, namely multidisciplinary diagnosis and evaluation, multidisciplinary prevention and treatment, and specific treatment of common malignant tumor-associated acute abdomen. The diagnosis and evaluation section mainly includes oncology, imaging diagnosis and surgical perioperative evaluation. The prevention and treatment section mainly includes the prevention of malignant tumor-associated acute abdomen, the principle of treatment based on surgery, anti-tumor therapy-induced acute abdomen, as well as the prevention and management of special biological types of malignant tumor-associated acute abdomen. The last part discusses specific treatment of malignant tumor-associated acute abdomen such as gastrointestinal obstruction (surgery, palliative care, endoscopic or interventional surgery), gastrointestinal perforation (perioperative and surgical treatment), gastrointestinal bleeding (medical treatment, endoscopic surgery, interventional surgery, and surgical treatment), biliary system-associated acute abdomen (treatment of acute cholangitis, acute cholecystitis, and gallbladder perforation), and rupture of liver cancer (general treatment, transarterial embolization, and surgical treatment). We hope this consensus will help clinicians to understand the multidisciplinary standardized diagnosis and treatment of patients with malignant tumor-associated acute abdomen and to serve as a practical reference.