This study aims to synthesize the benefits of surgery plus extensive intraoperative peritoneal lavage (EIPL) for patients with gastric cancer compared with surgery alone. We searched Pubmed, Embase, Web of Science, Cochrane library, ClinicalTrials.gov and World Health Organization International Clinical Trials Registry Platform (ICTRP) for randomized controlled trials from 2000 to 2021 according to the inclusion and exclusion criteria. The reference lists of studies meeting the criteria were also screened for additional studies. The quality of these studies was assessed by the Cochrane Collaboration Risk of Bias Tool. An inverse-variance random-effects model of DerSimonian and Laird was used to synthesize the HRs and corresponding 95% CIs of short-term outcomes: hospital mortality and postoperative complications. For long-term outcomes (peritoneal recurrence and 3-year or 5-year overall survival rate), narrative synthesis was used. 4 of 43 studies were included for quantitative analysis. For short-term outcomes, the pooled HRs of hospital mortality and postoperative complications are 0.422 (95%CI: 0.037, 4.790) and 0.774 (95%CI: 0.376, 1.592). For long-term outcomes, despite the inconsistent results, patients receiving EPIL did not have reduced peritoneal recurrence and 3-year or 5-year overall survival rate. Compared with surgery alone, surgery plus EIPL does not have more benefits for patients with gastric cancer.