Thermal degradation of six typical municipal solid waste (MSW) components (tire rubber (TR), recycled polyvinyl chloride pellets (PVC), wood sawdust (WS), paper mixture (PM), kitchen waste (KW) and textile (TE)) in CO2 and N-2 atmospheres is studied by using a thermogravimetric analyzer (TGA) combined with Fourier transform infrared (FTIR) spectrometer. Below 600 degrees C, CO2 behaves as an inert atmosphere and,samples display similar weight loss behavior in both atmospheres. In this temperature range, the gas species and variations of FTIR absorbance depend on the waste composition rather than atmosphere type. Most of gases display identical evolution trends in both N-2 and CO2, and the experience for pyrolysis in N-2 can also be used for pyrolysis in CO2, and simply replacement of N-2 by CO2 can't improve the pyrolysis performance. Above 600 degrees C, atmosphere changes not only the location of the DTG peak but also its formation mechanism, and CO2 behaves as a reaction atmosphere. In the later thermal degradation, the growth rate of CO absorbance in CO2 is significantly faster than in N-2, indicating waste pyrolysis in CO2 can increased the syngas production at higher temperatures.