Abstract: Reverse transcription-polymerase chain reaction(RT-PCR)method was used to amplified the IFN- gene fragment from lung tissue of Muscovy duck,then cloned to pMD18-T vector,the positive clones were confirmed by PCR and restriction enzyme digestion,the obtained sequence were analyzed by the Lasergene v7.1 DNAStar software.The results showed that,the Muscovy duck IFN- gene encoding a 576 bp open reading frame(ORF),which was first reported in the world.The nucleotide had higher similarity ranging from 95.5% to 97.7% among different goose species,also had higher similarity ranging from 97.0% to 97.7% among different duck species;however,the ducks and geese IFN- gene had its' own phylogentic lineage,which means,the IFN- gene had strictly specificity in different species.