Chlorinated hydrocarbons have been widely utilized due to their excellent physical properties and stability as solvents, coolants, propellants or raw materials ets. One of major problems in disposing of them is safe destruction of collection of recyclable components. One of most feasible methode for waste chlorinated organics is thermal treatment. In this study, experimental and theoretical analyses have been tried to investigate several fundamental operating parameters including temperature, residence time and background conditions like existence of oxygen. Vinyl chloride and trichloroethylene (TCE) were teated to observe their reaction mechanism. Vinyl chloride started to decompose at 725℃, and 99% of initial amount was decomposed at 830℃, 1 sec in pyrolytic environment, produing C₂H₂ and HCI mainly and C₂HCI, C₂H₄, H₂ as byproducts depending on experimental conditions. TCE, on the other hand, produced C₂Cl₂, C₂Cl₄, HCI at pyrolytic conditions and CO and CO₂ additionally through COCI radical reactions at oxidative conditions. The supply of oxygen lowered the destruction temperature of TCE and C₂Cl₄ could be considered as an indirect indicator of TCE decomposition.