Porcine reproductive and respiratory syndrome (PRRS) caused by PRRSV is detrimental to economy. There are two types of PRRSV, being North American (NA) type and Europe (EU) type. EvaGreen-based real time RT-PCR protocol was established for quantifying and genotyping PRRS virus, in which F7 and R7 primers were designed on ORF7 of the virus. A standard curve used in the assay was created by a plasmid DNA template. The whole ORF7 of PRRSV genome was inserted into pGEM T Easy plasmid, then, cloned into E. coli DH5a. The sensibility of the assay was 10 exponent 1 copies/ul. The specificity of the assay was confirmed by using PCV (porcine circovirus) and PRRSV-free blood of pig. Genotyping of EU PRRSV and US PRRSV was based on the difference of melt temperature (Tm) in melt curve analysis. The Tm of EU PRRSV amplicon was 83.4°C and that of US PRRSV amplicon was 84.4°C. The results showed that EvaGreen-based real time RT-PCR assay could offer quick, sensitive and accurate results for quantifying and genotyping PRRS virus, which was used to determined genotypes and viral load of blood samples and swab from post weaning pigs.