OBJECTIVE： To evaluate the association between UGT1A1 gene polymorphism and irinotecan-induced 3-4 degree neutropenia， and to provide evidenced-based reference for clinical treatment. METHODS： Retrieved from CJFD， Wanfang database， VIP， PubMed， EMBase， Science direct and Cochrane library， related studies about UGT1A1＊28 and UGT1A1＊6 gene polymorphism and irinotecan-induced 3-4 degree neutropenia were collected. After data extraction and quality evaluation of included studies， Meta-analysis was conducted by using Review Man 5.3 software. RESULTS： A total of 29 studies were included， involving 2 408 patients. UGT1A1＊28 includ wild genotype TA 6/6（UGT1A1＊1/＊1）and mutations genotype TA 6/7（UGT1A1＊1/＊28）、TA 7/7（UGT1A1＊28/＊28），UGT1A1＊6 includ wild genotype GG and mutations genotype GA、AA. Results of Meta-analysis showed： the incidence of 3-4 degree neutropenia in UGT1A1＊28 and UGT1A1＊6 mutations genotype were significantly higher than wild genotype， with statistical significance [UGT1A1＊28：OR＝1.92，95％CI（1.52，2.44），P＜0.001； UGT1A1＊6：OR＝2.49，95％CI（1.46，4.26），P＜0.001]. Using medium-dose and high-dose of irinotecan， the incidence of 3-4 degree neutropenia in UGT1A1＊28 and UGT1A1＊6 mutations genotype were significantly higher than wild genotype， with statistical significance [UGT1A1＊28：OR＝2.06，95％CI（1.57，2.70），P＜0.001）；UGT1A1＊6：OR＝1.92，95％CI（1.35，2.74），P＜0.001]. Using low-dose of irinotecan， there was no statistical significance in the incidence of 3-4 degree neutropenia between UGT1A1＊28， UGT1A1＊6 mutations genotype and wild genotype [UGT1A1＊28：OR＝1.20， 95％CI（0.70，2.08），P＝0.51； UGT1A1＊6：OR＝3.19，95％CI（0.85，11.89），P＝0.08]. CONCLUSIONS： Using medium-dose and high-dose of irinotecan， UGT1A1＊28 and UGT1A1＊6 mutations will increase the risk of severe neutropenia in cancer patients. Using low-dose of irinotecan， there is no clear correlation between gene polymorphism and the neutropenia.