Idiopathic non-cirrhotic portal hypertension is a rare group of clinical syndromes characterized by clinical manifestations of portal hypertension in the absence of histological manifestations of liver cirrhosis, and with the exclusion of known intrahepatic and extrahepatic causes of portal hypertension. Importantly, its etiology and pathogenesis are unclear, but it has been determined to be related to the development of intrahepatic vascular disease. It is currently believed that possible pathogenic mechanisms include immune disorders, chronic infections, drug-related poisoning or injury, microthrombosis, genetic abnormalities, etc. The most common clinical manifestations are esophagogastric varices and splenomegaly. Ascites and hepatic encephalopathy are the least common. Laboratory test demonstrates anemia, leukopenia, and thrombocytopenia due to hypersplenism, and normal or mild liver function abnormality. In addition, in the preclinical stage, despite the presence of abnormal portal vein during liver biopsy, no signs of portal hypertension can be detected in some patients. Therefore, the diagnosis is based on the diagnosis of exclusion and mandatory liver biopsy. The overall prognosis of idiopathic non-cirrhotic portal hypertension is better than that of patients with liver cirrhosis, but symptomatic treatment (controlling gastroesophageal varices bleeding and preventing thrombosis) is still the main treatment.