Making Aigle in Switzerland as a case to assess earthquake damage to entire urban building, by studying the history of architecture and city planning of entire urban, we found that entire urban can be divided into two urban areas. One area is upstream urban of railway station, which was mainly developed around old urban, and the other area is lower urban of railway station, which was mainly developed after 1950s. Developing stages of the two areas are different. In each urban area, a study area is selected and balanced construction units of each building in the study area are calculated. Based on this, earthquake damage to entire urban building is calculated with European Macrosesmic Scale 1998 (EMS-98). To advance precision of assessment, in this article, relationship between type of structure of building and construction date is established first, which makes it easy to precisely determine type of structure of building according to construction date of building. It advances precision of earthquake damage assessment to building. There are 7900 residents in Aigle, the period of earthquake, whose seismic intensity is Grade VII, is 500 years. If earthquake, whose seismic intensity is Grade VII, occurs, it is possible that about 236 persons will injury badly or die and total property loss may be 117,720,000 Suisse Franc.