Peritoneal metastasis of gastric cancer is the main cause of death in gastric cancer patients. Peritoneal metastasis of gastric cancer is difficult to diagnose in its early stage due to lack of obvious clinical signs and symptoms, and poor treatment outcomes and prognosis are often associated with late stage peritoneal metastasis. Therefore, it is crucial to utilize effective early diagnostic tools and to improve the long-term outcomes and the prognosis of patients with advanced gastric cancer. Recently, systemic chemotherapy and intraperitoneal chemotherapy are the first line therapy, and cytoreductive operation plus abdominal cavity thermochemotherapy may be the best method in the treatment of peritoneal metastasis. However, conversion therapy has been gradually incorporated into the treatment of peritoneal metastasis of gastric cancer because of the better efficacy and the higher survival.