[Abstract] Objective To compare the efficiency of two RNA extraction methods in the MNV detection. Methods Trizol and QIAamp Viral RNA Mini Kit were used to extract RNA of intestine tissue from MNV infected mouse and RAW264.7 cells infected by MNV; the RNA concentrations by the two methods were compared; and the efficiency in MNV amplification were also analyzed between the two methods by one step RT-PCR with MNV specific primers. Results the intestine RNA concentration extracted by Trizol was higher than that by QIAamp Viral RNA Mini Kit; the concentration of RNA from MNV infected RAW264.7 by Trizol was lower than that by QIAamp Viral RNA Mini Kit. A specific MNV band can be amplified from RNA extracted by QIAamp Viral RNA Mini Kit, but not from RNA by Trizol. Conclusion QIAamp Viral RNA Mini Kit is more efficient in the extraction of MNV RNA.