A huge amount of building waste was generated by collapsed dwelling houses and dilapidated buildings after the Wenchuan earthquake which occurred on May 12, 2008, in Sichuan Province, PR China. In this paper, based on the field damage investigation in the earthquake-hit area, the relationship between different building structures and building waste produced is established and evaluated. A mathematical model to forecast the amount of building waste in the earthquake-hit area is preliminarily proposed, the type and the quantity of building waste are statistically analyzed from several aspects. The composition and distribution characteristics of building waste in the disaster area are thus described. Finally, considering the characteristics of building waste, some suggestions and applications on potential reuse and recycling of building waste are put forward. This will make the post-earthquake reconstruction engineering more ecological and economical.