Peritoneum is a common recurrent and metastatic site of gastric cancer, and peritoneal metastasis and recurrence may have significant impact on the outcomes of patients with gastric cancer. As the early state of peritoneal metastasis, the detection of peritoneal free cancer cells may serve as a reliable way to predict peritoneal recurrence, estimate prognosis and guide treatment. The research progress of intraperitoneal free cancer cells of gastric cancer is reviewed in this paper.