Abstract: Chickens intramuscularly inoculated with a avian influenza virus,A/goose/Guangdong/2/1996(H5N1),produced approximately 70% of morbidity and 60% of mortality, and had micropathological and ultrapathological lessions in some degree in multiple organs,such as, systemic hyperemia, congestion, haemorrhage, thrombosis, and cell degeneration,necrosis,and inflammation etc. As well as apoptosis was detected in pancreas, kidney, liver, heart, lung, cerebrum, intestines, thymus, spleen and bursa of fabricius etc.

Key words: H5N1 subtype avian influenza; pathology; apoptosis; chickens