Abstract: 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.