Abstract: A virus strain,E05,was isolated from oviduct mucosa of breeder Muscovy duck,which showed irregularity and reduction in egg-laying.The virus was identified as an egg-laying reduction syndrome virus(EDSV) by haemagglutination and haemagglutination inhibition tests.According to the conserved region of duck original EDSV sequence,a pair of primers was designed for PCR.The product of the PCR was ligated with T vector and introduced into competent cells.Positive recombinant was selected for sequencing.The sequence of PCR product was compared with that of the 100 kD gene found in GenBank nucleotide database.The result showed that the amplified product from the isolated virus was completely identical with the counterpart of the EDSV.