Abstract: Objective To evaluate the effect of high body mass index（BMI） on the prognosis of gastric cancer patients undergoing gastrectomy. Methods　PubMed，EMBASE，Scopus，Cochrane Library，WanFang and CNKI databases were searched to find related studies on the effect of high BMI on the prognosis of patients that undergoing gastrectomy for gastric cancer from inception to December 31，2018. According to the inclusion and exclusion criteria，screened the literature，extracted data and evaluated the quality. Meta-analysis was performed using Review Manager 5.3 software. Results A total of 35 literatures were included in the study，including 32 113 patients（11 356 females and 20 757 males） with primary gastric cancer. Meta-analysis showed that the risk of postoperative complications in patients with high BMI was significantly higher than that in patients with low BMI，whether it was open or laparoscopic gastrectomy（RR=1.29，95%CI：1.14-1.46，P<0.001；RR=1.24，95%CI：1.04-1.47，P=0.01）. The 5-year overall survival rate of patients with high BMI gastric cancer was lower than that in patients with low BMI gastric cancer（RR=0.87，95%CI：0.79-0.96，P=0.006），but high BMI had no significant effect on perioperative mortality in patients with gastric cancer（RR=0.79，95%CI：0.51-1.22，P=0.29）. Conclusions Patients with high BMI gastric cancer have a higher incidence of postoperative complications and a lower 5-year survival rate than those patients with low BMI gastric cancer，but no increase perioperative mortality.

Key words: Ｇastric cancer, Ｈigh body mass index, Complication, Ｐrognosis