【Abstract】 Objective To study the relationship between single nucleotide polymorphism (SNP) at rs4301112 locus of CD157/BST1 gene with the risk of childhood autism spectrum disorder (ASD). Methods 102 children with ASD from March 2017 to January 2019 in Affiliated Hospital of Xuzhou Medical University were treated as ASD group. 100 healthy children without neurodevelopmental disorders were taken as control group. The children with ASD were divided into mild to moderate group (66 cases) and severe group (36 cases) according to the results of Children Autism Rating Scale (CARS). The CD157/BST-1 locus rs4301112 in blood samples of children was sequenced by Sanger sequencing. The relationship between single nucleotide polymorphism (SNP) of CD157/BST-1 locus rs4301112 with the severity and risk of ASD were analyzed. Results The distribution frequencies of AG genotype and G allele at rs4301112 locus of CD157/BST-1 gene in ASD group was higher than that in control group (P＜0.05). Under dominant mode, the frequency of AG + GG genotype in ASD group was higher than that in control group (P＜0.05). The frequencies of AG genotype and C allele in severe ASD group was higher than that in mild and moderate ASD group (P＜0.05). There was no significant difference in genotype frequencies of AA and GG and frequencies of A allele between severe group with mild and moderate group (P＞0.05). Logistic regression analysis showed that AG genotype was a risk factor for ASD. Conclusion The AG genotype and G allele at rs4301112 locus of CD157/BST-1 gene may be related to the risk and severity of ASD.