To identify molecular makers related to the disease-resistance traits after the porcine reproductive and respiratory syndrome virus (PRRSV) infection,a total of 159 healthy piglets from Large White × Tongcheng advanced generation intercross population were infected with PRRSV and genotyped with the “Zhongxin No.1” SNP chip.The lymphocyte percentages at different days post-infection (dpi) were measured as disease resistance indicator.The results showed that single nucleotide polymorphisms (SNPs) rs81257542,rs334594334 and rs329240026 in DDX17 and BTG1 genes were significantly associated with lymphocyte percentages (P<0.05) at different time points post PRRSV infection.Allele C in rs81257542,allele A in rs334594334,and the combined genotype CC-AA were the dominant allele and dominant genotype,the more the dominant allele,the higher lymphocyte percentage and stronger disease resistance.One-step Tetra-primer ARMS-PCR method was further developed to rapidly genotype rs81257542 and rs334594334.In conclusion,the SNPs of rs81257542 and rs334594334 are potential molecular markers for the percentage of blood lymphocyte associated with PRRS resistance,and the detection method can achieve rapid screening of dominant genotypes.