Avifauna changes in 30 years in Xi′an were analyzed based on two bird surveys by line transect method conducted from 1977 to 1980 and 2004 to 2007.Totally,138 species were recorded in the first bird survey and 149 species in the second survey in four types of habitat,namely shallow hill zone,village/cropland,open water,and city building zone.Highest bird richness was found in the shallow hill zone where the ecological environment was undisturbed,while in city building zone the bird richness was the lowest in both of the bird surveys.Comparing with the result got in the first survey,24 species were not found and 34 birds have been added in the list,while 24 birds recorded in the first survey have not been found in the second survey. The species richness and abundance in each habitat was different for the two surveys. More bird species feeding on foliage have been recorded in the city building zone and more insectivorous birds have been recorded in the shallow hill zone in the second survey comparing with the result of the first bird survey.More attention should be paid to the urban bird conservation as the size of city expanded speedily.