Gastric cancer is one of the common malignant tumors in China, and its incidence rate ranks first among all types of tumors in China. Early stage gastric cancer is mostly asymptomatic or has only mild symptoms. When clinical symptoms are obvious, the disease is already in advanced stage. Stomach cancer can metastasize, so what are the ways of metastasis of stomach cancer? There can be four ways of metastasis of gastric cancer, usually lymphatic metastasis and direct spread are the main ones, and in advanced stage, it can also be metastasized through bloodstream. In addition, cancer cells can be directly planted in the abdominal cavity. (1) Direct spread: After the cancer invades the stomach wall, it will develop in the longitudinal direction and break through the plasma membrane layer, and can directly invade the adjacent organs and tissues, with the greater omentum, liver, pancreas and transverse colon being the most common, followed by the jejunum, diaphragm and even the abdominal wall. The direct spread is related to the surgical method and whether it can be resected radically. Generally, the spread to the adjacent organs, such as liver, can be resected surgically when the scope is small and limited, but it is difficult to remove all of them when the scope is large. (2) Lymph node metastasis: It is an important way for gastric cancer to spread, and it occurs earlier. As the cancer grows, the deeper and wider it invades the stomach wall, the more chances of metastasis. According to the order of metastasis, there are 3 stations or 3 groups. The first group (station) is the closest to the tumor and is the superficial group of lymph nodes attached to the stomach wall, which usually occurs when the gastric cancer is confined to the submucosa. The second group (station) is the deep group of lymph nodes draining the superficial lymph nodes, which may occur when the gastric cancer invades the muscular layer. The third group (station) includes lymph nodes around the paracavernous artery, abdominal aorta, hepatic portal, mesenteric root and middle colonic artery; distant lymph node metastasis may also occur, such as left supraclavicular lymph node. This group of metastases mostly occurs when the cancer invades into the plasma membrane. Generally speaking, the chance of radical treatment is lost when the third group of lymph node metastasis occurs. (3) Hematogenous metastasis: some patients may have gastric cancer cells or cancer emboli to other organs of the body through blood circulation. It can metastasize to liver, lung, bone, kidney, spleen, brain, meninges, skin, and also to ovary, forming Krukenberg’s carcinoma or mucinous cell carcinoma of ovary. Hematogenous metastasis occurs mostly in the late stage of gastric cancer. In addition to treating the primary foci, metastatic foci also need to be treated. (4) Intra-abdominal implantation metastasis of gastric cancer cells: in a few cases, the cancer tumor breaks through the plasma membrane of gastric wall and appears necrotic shedding of cancer tissue to other organs and peritoneum, and implantation growth can occur; cancerous peritonitis can occur in late stage with bloody ascites, and sometimes cancer cells can be found in the extracted ascites. Patients with implantation metastasis are all in advanced stage, which makes treatment more difficult. Intra-abdominal injection of chemotherapy drugs is often given, but due to extensive metastasis, it can often only prolong life but not cure.