BACKGROUND: Latest research on ankylosing spondylitis (AS) indicates a link between the B3GNT2, PSMG1 genes and susceptibility to AS among western populations. However, the association of these three genes with AS in eastern populations remains insufficiently explored. It is necessary to replicate these studies in other populations. Consequently, we chose tagSNPs in these three genes in the Chinese Han population to be sequenced. PURPOSE: We tried to find the SNP loci that are associated in both eastern and western populations through repeated experiments. Furthermore, our research extended to examining the link between these genes and the severity of AS. This study aimed to evaluate the association between the tagSNPs of B3GNT2 (rs10865331, rs6545925, rs467250), the rs4676410 SNP on GPR35, and the rs4816648 SNP of PSMG1 with AS susceptibility and disease activity in a Chinese Han population. METHOD: We collected blood samples from 497 patients with AS and 498 control subjects and sequenced 5 tagSNPs in B3GNT2, 1 tagSNP in GPR35, and 6 tagSNPs in PSMG1. RESULT: Within the five selected tagSNPs of B3GNT2, the rs10865331, rs6545925, and rs4672501 tagSNPs are associated with susceptibility to AS. Additionally, the rs4672501 SNP is not only associated with susceptibility to AS, but also with the severity of AS. For the first time, we find that the rs4676410 SNP on the GPR35 gene is associated with susceptibility to AS, but not associated with the severity of AS in the Chinese Han population. We find for the first time that the rs4816648 SNP of the PSMG1 gene is associated with both susceptibility and severity of ankylosing spondylitis. CONCLUSION: B3GNT2 and PSMG1 genes are related to both susceptibility and severity of AS. The GPR35 gene is related to susceptibility to AS in the Chinese Han population, which corroborates the findings of research conducted in western populations.