Abstract: OBJECTIVE To investigate the correlation between matrix metalloprotein-9（MMP-9） 1562 C/T and susceptibility to sepsis and the prognostic value of serum MMP-9. METHODS Total of 65 patients with sepsis admitted to the Department of Intensive Medicine of the Affiliated Hospital of Ningbo University School of Medicine from Feb. 2018 to Feb. 2020 were recruited as the research group, and 60 patients having major surgical operations without sepsis during the same period were in the control group. MMP-9-1562 C/T locus genotype and allele frequency were detected by using Taqman probe method. Receiver operating characteristic（ROC） was used to evaluate the prognostic value of serum MMP-9 in the study group. Serum level of MMP-9, the Sequential Organ Failure Score（SOFA）, Acute Physiological and Chronic Health Score（APACHE II） score, blood lactic acid, C response Correlation of protein（C reactive protein, CRP）, procalcitonin（PCT） and neutrophil/lymphocyte ratio（NLR） were analyzed. RESULTS The CC genotype and C allele frequency in the study group（47.06% and 58.09%） were significantly lower than that in the control group, whereas the TT genotype and T allele frequency were significantly higher than that in the control group（P＜0.05）. After adjusting for confounding factors such as age and gender, we found that patients with CT and TT genotype and T alleles had an increased risk of sepsis than that with CC genotype and C alleles. Serum MMP-9 level, SOFA, APACHE Ⅱ, blood lactate, CRP, PCT and NLR levels in patients with CT+TT genotype at MMP-9-1562 C/T locus were significantly higher than that with CC genotype（P＜0.05）. ROC analysis showed that serum MMP-9 level had a good predictive effect on the prognosis of patients with sepsis, with an area under the curve of 0.790 and 95% CI value of 0.705 to 0.875. CONCLUSION MMP-9-1562 C/T locus gene polymorphism may be associated with sepsis susceptibility and should be verified by a larger sample. Serum MMP-9 level may have certain predictive value for the prognosis of patients and be worthy of clinical promotion.