AIM: To apply the small interfering RNAs targeting NP or/and PA gene of influenza virus to inhibit the expression of NP or/and PA and multiplication of influenza virus in Madin-Darby canine kidney (MDCK) cells. METHODS: The recombinant plasmids, pEGFP/NP, pGenesil/PA and pEGFP/NP+ PA were constructed and transfected into MDCK cells. The transfected MDCK cells were infected with subtype H5N1 strain. The transfection efficiency was determined using fluorescence microscopy. The expression levels of NP gene wer...