Influenza A virus is a widespread pathogen,but current vaccines and drug therapy are of limited value. RNAi may provid a novel route to control it since RNAi can inhibit gene expression high-efficiently and specificly. A recombinant plasmid with a short hairpin RNA(shRNA)targeting at the nuclear protein gene of the virus was constructed and identified by enzyme digestion and sequence analysis.The hemagglutination(HA) titre and TCID 50 of the virus in chicken embryo fibroblastic(CEF)cells transfected with the plasmid was lower than that nontransfected with the plasmid.It showed that the plasmid could specifictly inhibit the virus production in CEF cells.