AIM: To evaluate the efficacy of intravitreal injection of conbercept (IVC) and ranibizumab (IVR) in patients with diabetic macular edema. METHODS: Reviewers have searched 12 databases, including PubMed, Medline, EMBASE, Web of Science, Springer, ScienceDirect, OVID, Cochrane Library, ClinicalTrials.gov, cqVIP, WanFangdata and China National Knowledge Infrastructure (CNKI), up to December 28, 2018. RevMan 5.3 (Cochrane Library Software, Oxford, UK) was employed for statistical analysis. Fixed and random effects models were applied to assess heterogeneity. Odds ratio (OR) was applied for dichotomous variables; weighted mean difference (WMD) was applied for continuous variables. The confidence interval (CI) was set at 95%. Central macular thickness (CMT) and best-corrected visual acuity (BCVA) were employed to analyze the improvement of DME patients. Inclusion criteria for picking out studies were retrospective studies and randomized controlled trials (RCTs) that compared IVC and IVR for the treatment of diabetic macular edema. RESULTS: Four retrospective studies and five RCTs were included with a total of 609 patients. No statistically significant difference was observed in mean CMT and mean BCVA in the baseline parameters [BCVA (WMD: -0.48; 95%CI: -1.06 to 0.10; P=0.1), CMT (WMD: -0.83; 95%CI: -15.15 to 13.49; P=0.91). No significant difference was found in the improvement of BCVA and adverse event (AE) in IVC group, compared with IVR group after treatment of loading dosage [the 1st month BCVA (WMD: 0.01; 95%CI: -0.26 to 0.27; P=0.96), the 3rd month BCVA (WMD: -0.04; 95%CI: -0.14 to 0.06; P=0.46); the 6th month BCVA (WMD: -0.24; 95%CI: -1.62 to 1.14; P=0.73)], AE (OR: 0.84; 95%CI: 0.38 to 1.84; P=0.66)]. A slight difference was found in the effectiveness rate (OR: 1.70; 95%CI: 0.97 to 2.96; P=0.06), There were statistically significant differences between IVC and IVR treatment in terms of CMT [1st month CMT (WMD: -19.88; 95%CI: -27.94 to -11.82; P<0.001), 3rd month CMT (WMD: -23.31; 95%CI: -43.30 to -3.33; P=0.02), 6th month CMT (WMD: -74.74; 95%CI: -106.22 to -43.26; P<0.001)]. CONCLUSION: Pooled evidence suggests that both IVC and IVR are effective in the therapy of diabetic macular edema and affirms that IVC presents superiority over IVR therapy in regard of CMT in patients with diabetic macular edema, but no statistically significant difference with regard to visual improvement. Relevant RCTs with longer-term follow-up are necessary to back up our conclusion.