The influence of calcium stearate on curing characteristics,physical mechanical properties,crosslink densities,heat-air aging properties,thermal stability and thermal degradation kinetics of epoxidized natural rubber with epoxidation of 25 mol %was studied in the semi-efficient vulcanization.The results show that the compound has the longer scorch time(tS1),farer vulcanization rate,higher crosslink density and better physical mechanical property,when the addition of calcium stearate is 1phr.With the loading of calcium stearate increasing,heat-air aging properties,apparent activation energy of thermal degradation,and thermal stability of ENR25 vulcanizates are enhanced.