Abstract: OBJECTIVE To analyze the relationship between body mass index（BMI） and hypoxia-inducible factor 1α（HIF-1α） gene polymorphisms and acute kidney injury（AKI） in patients with severe infection. METHODS A total of 122 patients with severe infection diagnosed and treated in the People’s Hospital of Langfang from Jan 2017 to Jun 2019 were recruited. The patients were divided into the AKI group（n=53） and non-AKI group（n=69） according to whether they were complicated with AKI. The BMI index was compared between the two groups, and the locus polymorphism of single nucleotide polymorphism（SNP） of HIF-1α gene was detected. The relationship between BMI index and HIF-1α gene polymorphism and AKI in patients with severe infection was analyzed. RESULTS The BMI index in the AKI group was significantly higher than that in the non-AKI group（P＜0.05）. The CC genotype distribution frequency and C allele frequency at rs11549465 locus of HIF-1α gene in the AKI group were significantly lower than those in the non-AKI group（P＜0.05） while the CT+TT genotype distribution frequency and T allele frequency were significantly higher than those in the non-AKI group（P＜0.05）. The GG genotype distribution frequency and G allele frequency at rs11549467 locus of HIF-1α gene in the AKI group were significantly lower than those in the non-AKI group（P＜0.05） while the GA+AA genotype distribution frequency and A allele frequency were significantly higher than those in the non-AKI group（P＜0.05）. Under the superdominant or dominant model, there were significant differences in the distribution frequencies of genotypes at rs11549465 locus and rs11549467 locus of HIF-1α gene between the AKI group and non-AKI group（P＜0.05）. Compared with CC and GG genotypes, patients with severe infection carrying CT+TT and GA+AA genotypes had higher risk of AKI. Multivariate Logistic regression analysis showed that BMI index, CT+TT genotype at rs11549465 locus and GA+AA genotype at rs11549467 locus of HIF-1α gene were risk factors affecting the occurrence of AKI in patients with severe infection. CONCLUSION BMI index and CT+TT genotype at rs11549465 locus and GA+AA genotype at rs11549467 locus of HIF-1α gene may increase the risk of AKI in patients with severe infection.