Abstract: NGO (non-governmental organization), as non-profit social organizations which are independent of the government and the market, have played an important role in the disaster relief and post-disaster reconstruction work.This article, starting from the background of the reconstruction work of earthquake-stricken areas in Sichuan and based on the surveys of domestic and international NGO in Shifang, Mianzhu of Sichuan province, which are two hard-hit areas of the "5.12" earthquake, makes an analysis of the roles the NGO played during the disaster relief work and post-disaster reconstructions and comes up with the conclusion that NGO will undertake much more important tasks during the process of post-earthquake reconstruction than the earthquake relief.