Coat Protein coding gene of Potato Virus M（PVM） was cloned from leaf of infected potato plant by RT-PCR, and it was composed of 912 base pairs. It was subcloned to pET-28b（+）, the construct was then transformed into E.coli Rosetta. Induced by IPTG, coat protein was expressed as a 33 kDa protein. After the purification by Ni-NTA resin, the purified protein was used as the antigen to immunize rabbits. The serum titer reached to 1:64 000 after the forth immunization. These anti-serums can recognize specifically natural PVM that was proved by ELISA and Western blot analysis. The preparation of polyclonal antibody against PVM laid a foundation for the establishment of rapid detection method for PVM.