H3N2, H5N1 and H5N8 virus were widespread epidemic in South Korea. Especially in 2014 Korea, the serious outbreak of avian influenza caused by H5N8 took place, effecting not only birds but also dogs. Antibody of H5N8 virus was found on a dog which differentiated the virus from existing H3N2 canine virus. At this point, we wanted to find out why H5N8 was self-medicated in dogs and whether H5N8 would cross species boundaries and be fatal to dogs or other species. While H5N1 is avian influenza like H5N8, many cases of fatal infections among dogs caused by H5N1 have been reported. Another kind of avian influenza, H3N2 is most common type of canine influenza in Asia. With the use of decision tree and apriori algorithm, we could find out characteristics of H5N8 by comparing it with H5N1 and H3N2.