Objective: To evaluate the effect of prolonging the insertion length of gastric tube in the rescue of acute organophosphorus pesticide poisoning (AOPP) and its clinical efficacy. Methods: The keywords, citations and related studies of all the randomized controlled trials (RCT) about prolonging the insertion length of gastric tube in the rescue of patients with AOPP were retrieved on the databases, including PubMed, EMBASE, Cochrane Library, Chinese Biomedical Literature Database (CBM), Chinese Journal Full-text Database (CNKI), Wanfang Database, Vip Database. The RCTs that fit the inclusion criteria were performed the quality evaluation according to the Cochrane systematic review and scored by the Jadad scale. The time for first liquid sucking out, the total gastric lavage time, the incident of bloody liquid in lavage fluid, the incidence of upper abdomen discomfort and the success rate of gastric lavage were analyzed. The meta-analysis was performed on the RevMa5.0 software and the data were dealt with fixed effect model or random effect model. The risk ratio (RR), standardized mean difference (SMD) and 95% CI were also calculated to determine the clinical efficacy of prolonging the insertion length of gastric tube in the rescue of patients with AOPP. Results: Eventually, 14 RCTs with 1504 cases were included. Meta-analysis showed that indicators including the time for first liquid sucking out (pooled SMD=-1.88; 95% CI, -2.04 to -1.73), total gastric lavage time (pooled SMD=-2.26; 95% CI, -2.42 to-2.10), the incident of bloody liquid in lavage fluid (pooled RR= 0.17; 95% CI, 0.08 to 0.33), the incidence of upper abdominal discomfort (pooled RR= 0.26; 95% CI, 0.16 to 0.40) and the success rate of gastric lavage (pooled RR= 0.24; 95% CI, 0.15 to 0.38) of the patients treated with prolonged gastric tube were all superior to those treated with the traditional gastrictube insertion length. Conclusion: Prolonging the length of gastric tube insertion could shorten the time for first liquid sucking out and the total gastric lavage time, increase the rate of patients with bloody liquid in lavage fluid as well as the success rate of gastric lavage and reduce the incidence of upper abdominal discomfort.