Abstract: This paper introduces the thermal stability of polycarbonates (PC) and its affecting factors. The effect of some additives，such as coupling agent: methyltrimethoxy silane and tetrabutyl orthotitanate，flame retardant: potassium diphenylsulfone sulfonate (KSS) and poly(aminopropylphenylsilsesquioxane) (PAPSQ) on the thermal stability of PC are discussed. The analytical methods of the decomposition kinetics of the polymer: Kissinger method and Ozawa method are introduced. The recent researches and major results in the thermal degradation mechanism of PC are reviewed.