In order to develop a rapid and simple method to detect porcine reproductive and respiratory syndrome virus genotype 2（PRRSV-2），3 pairs of primers were designed according to the conserved sequence of its ORF6 gene，and a reverse transcription recombinase-aided isothermal amplification（RT-RAA）assay was established with the optimal primers after optimizing theirs reaction conditions. The results showed that，by the method，target sequence could be amplified at 40 ℃ for 25 minutes；with its strong specificity，no cross-reaction with pseudorabies virus（PRV），porcine parvovirus（PPV），porcine circovirus type 2（PCV-2），transmissible gastroenteritis virus（TGEV）and porcine epidemic diarrhea virus（PEDV）was observed；with high sensitivity，the detection limit was 2×100 TCID50/μL，which was 10 times lower than traditional RT-PCR；39 clinical samples suspected of PRRSV infection were detected by the method，25 positive samples were identified，which was consistent with the results by the quantitative real-time RT-PCR established previously. In conclusion，the established method，with simple operation，strong specificity，high sensitivity and good clinical applicability，supported the rapid diagnosis of PRRSV infection as a new technical tool.