In hypersplenism, the spleen is significantly larger, usually tens to hundreds of times larger than normal. Especially in portal hypertension, the blood flow to the spleen is obstructed, the splenic sinuses are open, the spleen is stagnant, and a large amount of blood is stored in the enlarged spleen, sometimes up to several thousand milliliters. The causes of giant spleen syndrome are: 1. Infectious splenomegaly. Various acute and chronic infections such as typhoid fever, paratyphoid fever, black fever, schistosomiasis, malaria, viral hepatitis, sepsis, late syphilis, etc. 2. Depressed hemorrhagic splenomegaly. Zonti’s syndrome, liver cirrhosis, chronic heart failure leading to cardiogenic cirrhosis, chronic constrictive pericarditis, portal vein or splenic vein thrombosis. 3. Hyperplastic splenomegaly. It is seen in certain blood diseases such as leukemia, hemolytic anemia, malignant lymphoma, etc. 4.Other. Malignant tumors of the spleen are rare, splenic cysts, disseminated lupus erythematosus, dermatomyositis, polyarteritis nodosa, Gaucher’s disease, etc. Because the cause of large spleen is more complicated, except for a few people who are physiological, all of them should look for the cause under the guidance of doctors and should be reviewed regularly.