Psoriasis vulgaris (PsV), also known as plaque psoriasis, is a life-threatening autoimmune skin disease. Inflammatory factors may contribute to the development of PsV. Present study aimed to explore the association of endoplasmic reticulum aminopeptidase 1 (ERAP1) gene polymorphisms (rs26653 and rs27524) with PsV susceptibility in a Chinese Han population. Subgroup analysis was also performed based on the onset of PsV.Present case-control study included 143 patients with PsV and 149 healthy controls. Direct sequencing method was used for genotyping ERAP1 polymorphisms. Chi-squared test was used to estimate the association between ERAP1 polymorphisms and PsV susceptibility. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess association strength.The polymorphism rs26653 was positively correlated with PsV susceptibility (CC vs GG, P = .047, OR = 1.964, 95% CI = 1.006-3.834; C vs G, P = .042, OR = 1.403, 95% CI = 1.011-1.946). Meanwhile, its CC genotype and C allele were positively associated with the early onset of PsV (P = .036, OR = 2.080, 95% CI = 1.044-4.145; P = .034, OR = 1.443, 95% CI = 1.028-2.024) and increased PsV risk in the subgroup with family history (P = .029, OR = 2.149, 95% CI = 1.075-4.296; P = .027, OR = 1.466, 95% CI = 1.044-2.059).ERAP1 gene rs26653 polymorphism may increase the risk of PsV in Chinese Han population.