The effects of dibutyltin dilaurate (DBTL) on the dehydrochlorination (DHC) reaction of chlorinated natural rubber (CNR) from latex were studied by measuring the HCl evolving rate during the thermal degradation of CNR and determining the amounts of cyclic conjugated dienes formed on the CNR molecular chains. During the early stage of thermal degradation of CNR at 150 oC, the HCl is eliminated and the cyclic conjugated dienes are formed on the CNR molecular chains. Under the effects of DBTL, the HCl evolving rates in the early stage of thermal degradation of CNR can be reduced while the amounts of cyclic conjugated dienes formed on the CNR molecular chains can be increased. Under the effects of the mixtures by compounding DBTL with the barium stearate or 2,2-methylene-bis-(4-methyl-6-tert-butyl-phenol), not only the HCl evolving rate from CNR, but also the formation of cyclic conjugated dienes were decreased, which indicates that compounding mixtures have shown to have synergistic functions against the thermal degradation of CNR.