Two grades of epoxidized natural rubber (ENR), namely, ENR 25 and ENR 40 were mixing through adding 0-5 phr calcium stearate. The effect of calcium stearate concentration on cure characteristics of ENR was studied. The cure properties were determined by Moving Die Rheometer (MDR 2000) at 150°C. It showed that the scorch time (TS1) for ENR 25 and ENR 40 increased to a maximum value at 1 phr of calcium stearate, and further addition of calcium stearate maked it decrease. The cure time (T90), maximum torque (MH) and torque difference (MH﹣ML) of ENR decreased with increasing calcium stearate loading. For a fixed calcium stearate concentration, the scorch time (TS1) and cure time (T90) of ENR 40 were shorter than that of ENR 25, which is attributed to the activation of an adjacent double bond by the epoxide group in ENR. The results indicate that the effect of calcium stearate concentration on the cure characteristics of epoxidized natural rubber is remarkable.