Abstract: Objective]To study porcine reproductive and respiratory syndrome virus (PRRSV)genetic variation to monitor the prevalence of PRRSV in Xinjiang and provide assistance to PRRSV serology.[Method]We used RT-PCR method for the separation of 18 PRRSV ORF7 gene which was amplified,cloned and se-quenced to analyze the ORF7 gene variation[Results]The 18 PRRSV ORF7 sequence mutation type belonged to North America type.They had different genetic strain relations with the international standards and national standards strains.XJzx 4 and XJzx 1 had a closer genetic relationship with the international standard strains 01NP1.2,PA8,VR-2332 and LMY.Except XJzx1,XJzx14,the rest strains had close relationships with the mainland strains BJsy06,GD,HB-1sh 2002,HuN,JXA1,LN,NX06 and SX2009,so it could be inferred that they evolved from the strains in mainland China.[Conclusion]It is hypothesized that local pop PRRSV strains are derived from different regions.We have not detected PRRSV ORF7 gene deletion mutation in Xin-jiang.