In this study， the influence of betaine (N，N，N-trimethylglycine， non-rubber component in natural rubber) on the curing characteristics， tensile properties and thermal stability of polyisoprene rubber (IR) was investigated. Compared with the IR compound without betaine， the curing rate of the compound with betaine IR increased significantly， the crosslink density increased， tensile properties were improved and the thermal stability was slightly improved. The recommended addition level of betaine was 0.5 phr.
