It is shown from the investigation for the characteristics of the physics & the thermal treatment process about MSW in Chongqing:The complex components exist in MSW. The MSW have the characteristics, such as higher water, ash and lower heat value. And the bubbing temperature zone about the volatility of the organic matter is obviously but the others are not. The optimum relationship exists among the temperature, the size and the staying time of the MSW. The furnace temperature and constructure play very important roles for the clean combustion of the MSW.