OBJECTIVE To systema tically evaluate the efficacy and safety of blinatumomab for acute lymphoblastic leukemia （ALL）in order to provide evidence-based reference for clinical use. METHODS Retrieved from PubMed ，Embase，Web of Science，the Cochrane Library ，CNKI，Wanfang database and CBM during the inception to February 3，2022，randomized controlled trials （RCTs）and cohort studies of blinatumomab （experimental group ） versus conventional chemotherapy （control group ）in the treatment of ALL were collected. After literature screening and data extraction ，the quality of RCTs was evaluated by the risk bias evaluation tool recommended by Cochrane handbook 5.1.0，and the quality of cohort studies was evaluated by the Newcastle-Ottawa scale （NOS）. Meta-analysis was performed by RevMan 5.4 software. GRADE grading system was used to evaluate the evidence quality of outcomes. The publication bias was analyzed by inverted funnel plot. RESULTS A total of 8 studies were included ，involving 3 RCTs and 5 cohort studies ，with a total of 2 841 patients. Results of Meta-analysis showed that the overall survival rate more than one year [RR ＝1.30，95％CI（1.14，1.48），P＜0.000 1]，relapse-free survival rate [RR ＝1.78，95％CI（1.50，2.12），P＜0.000 01]，complete remission rate [RR ＝1.42，95％CI（1.11，1.82），P＝0.006]，the incidence of tremor [RR ＝16.98，95％CI（2.17，133.12），P＝0.007]，and the incidence of cytokine release syndrome [RR ＝14.11， 95％CI（3.43，58.01），P＝0.000 2] in trial group were all significantly higher than control group ，but there was no statistical significance in the incidence of headache between two groups [RR ＝1.31，95％CI（0.66，2.59），P＝0.44]. The incidence of adverse events with grade more than or equal to 3，infection，stomatitis，thrombocytopenia，febrile neutropenia ，anorexia， constipation，diarrhea，abdominal pain ，hypokalemia in trial group were significantly lower than control group （P＜0.05）. The incidence of cough ，rash and hypogamma globulinemia and fever in the trial group were significantly higher than control group （P＜0.05）. There was no statistical significance in the total incidence of adverse events ，sepsis，anemia，leucopenia，neutropenia， lymphopenia，nausea，vomiting，hyperglycemia，hypotension，hypertension，elevated transaminase or epistaxis between two groups（P＞0.05）. Results of subgroup analysis by study type showed that the overall survival rate ，relapse-free survival rate and complete response rate （except for cohort studies ）of patients in trial group were significantly higher than control group in both RCTs and cohort studies （P＜0.05）. The results of GRADE evaluation showed that the overall quality of index evidence included in this study was low. There was little possibility of publication bias in this study based on the publication bias analysis. CONCLUSIONS Blinatumomab is effective in the treatment of ALL ，with low incidence of infection and adverse events of digestive system ，but high incidence of tremor ，cough，rash，fever，hypoproglobulinemia and cytokine release syndrome. The evidence quality of the indicators included in this study is generally low .