Collapsing houses are one of the indicators to assess earthquake damage intensity. We monitored and analyzed the house collapse ratio and its spatial distribution in the Wenchuan Earthquake of May 12, 2008 by interpreting the aerial images. The results show that the houses were widely damaged, especially in Wenchuan County, Mianzhu City, Shifang City, and Pengzhou City in which Wenchuan County experienced the severest damage. We analyzed the spatial variation of the house collapse ratio and its relationship with earthquake intensity, geological structure, and stratum lithology. The results demonstrate that the house collapse ratio and the earthquake intensity have a positive relationship, which is controlled by the geological structure, stratum lithology, and building structure. Analysis of the collapsed houses over an extensive earthquake-damaged region using aerial images provides not only an effective assessment for the damages and losses, but also the foundation data for the analysis of earthquake intensity.