A strain of virus was isolated from faeces of diarrhea piglet using the Vero cells,and was identified as PEDV by RT-nested PCR,then was named as LJB/03.The 854 bp M gene of LJB/03 was amplified by RT-PCR,then was directly inserted into pMD18-T,and sequenced.The 854bp PM gene was sub-cloned into a prokaryotic expression vector pGEX-6P-1.A positive colony pGEX-6P-PM was translated into BL21(DE3)plysS.High-level expression of recombinant fusion protein was obtained after induced by IPTG.43 ku fusion protein was tested by SDS-PAGE and can be recognized by the positive serum of PEDV by Western-blot.Through gel thin layer scanning analysis,the amount of target protein is over 33.7%.So the recombinant M protein can be a valuable diagnosis or therapeutic agent for the diseases.