Abstract: Rare earth thermal stabilizer attracts more and more attention because it is non-toxic,environment-friendly,efficient and economical.Fatty acid rare earth thermal stabilizer is widely studied,however there seldom has any report about inorganic salt rare earth is used as thermal stabilizer.Thermal stability of polyvinyl chloride resin （PVC） upon doping ce-rium carbonate as well as compound binary-ingredient thermal stabilizer （i.e.cerium carbonate and tribasic lead sulfate） was determined by means of Congo red test method.Results showed that cerium carbonate could stabilize PVC because cerium can coordinate with multi Cl atoms which makes C-Cl bond in PVC stabilized.When cerium carbonate was used as thermal stabilizer alone with preferable proportion of 2%（mass fraction）,temperature of thermal degradation of PVC was 200 ℃ and thermal stable period was 646 s.The PVC doping compound stabilizer at a ratio of cerium carbonate:tribasic lead sulfate of 1∶1 （mass ratio） also displayed excellent thermal stability,decomposition temperature of PVC was 204 ℃,and thermal stable period was 2 211 s.